Review of low cost synthesis of perovskite solar cells/Fully spray-coated ITO-free organic solar cells for low-cost power generation

Review of low cost synthesis of perovskite solar cells

Fully spray-coated ITO-free organic solar cells for low-cost power generation[1][edit | edit source]

Abstract

We report on cost-effective ITO-free organic solar cells (OSCs) fabricated by a spray deposition method. All solution-processable layers of solar cells—a highly conductive poly(3,4-ethylenedioxythiophene):-poly(styrenesulfonate) (PEDOT:PSS) layer and a photoactive layer based on poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM)—were spray-coated. PEDOT:PSS anode films with various thicknesses were prepared by controlling the spray deposition time. The transmittance and sheet resistance of PEDOT:PSS anodes were varied from 89.0% to 67.4% and from 358 to 63.3 O/squares, respectively, corresponding to an increase in film thickness. The best device exhibited a high power conversion efficiency of 2.17% under 100 mW cm2 illumination with air mass (AM) 1. 5 global (G) condition. More importantly, the efficiency of the fully spray-coated OSC with the PEDOT:PSS anode was comparable to that of conventional ITO-based devices, demonstrating the feasibility of fabricating all-spray-deposited OSCs without a conventional spin-coating method and the possibility of replacing the costly vacuum-deposited indium tin oxide (ITO) with highly conductive polymer films fabricated by inexpensive spray deposition techniques.

Optically monitored spray coating system for controlled deposition of photoactive layer in organic solar cells[edit | edit source]

Abstract

A Spray deposition process equipped with an in-situ optical thickness monitoring system has been developed to fabricate the photo active layer of solar cells. Film thickness is monitored by a photodiode –LED couple after each deposition cycle. It is found thickness of spray deposited photo active film linearly increase with deposition cycle over a wide range of deposition conditions. After instrument calibration, optimization of the active layer thickness can be accomplished by simply setting the desired absorbance of the film. The simple process is used for rapid optimization of devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and Phenyl-C61-butyric acid methyl ester as well as P3HT and indene-C60 bis-adduct combination to achieve up to 4.21 % power conversion efficiency.

Organic photovoltaic modules fabricated by an industrial gravure printing proofer[edit | edit source]

Abstract

Large-area, flexible organic photovoltaic (OPV) modules are fabricated successfully by gravure printing in air, using an industrial-scale printing proofer of similar performance to commercial roll-to-roll printing processes. Both the hole transport layer, poly-3,4-ethylenedioxy-thiophene:poly(styrene sulfonic-acid) (PEDOT:PSS), and the active layer, poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM), are successively printed on indium tin oxide (ITO) coated polyethylene terephthalate (ITO/PET) substrates with evaporated aluminum (Al) top electrodes. The 45 cm2 modules, composed of 5 cells connected in series, show power conversion efficiency (PCE) of over 1.0%, in which the short-circuit current (Jsc) and open-circuit voltage (Voc) are as high as 7.14 mA/cm2 and 2.74 V (0.55 V per cell), respectively. The PCEs could be potentially improved by the further optimization of the layer interface, layer morphology and flexible substrate properties. The results suggest that gravure printing may be a suitable technique for fast commercial processing of large-area, flexible OPVs with high output.

[An inter-laboratory stability study of roll-to-roll coated flexible polymer solar modules^[2][edit | edit source]

Abstract

A large number of flexible polymer solar modules comprising 16 serially connected individual cells was prepared at the experimental workshop at Risø DTU. The photoactive layer was prepared from several varieties of P3HT (Merck, Plextronics, BASF and Risø DTU) and two varieties of ZnO (nanoparticulate, thin film) were employed as electron transport layers. The devices were all tested at Risø DTU and the functional devices were subjected to an inter-laboratory study involving the performance and the stability of modules over time in the dark, under light soaking and outdoor conditions. 24 laboratories from 10 countries and across four different continents were involved in the studies. The reported results allowed for analysis of the variability between different groups in performing lifetime studies as well as performing a comparison of different testing procedures. These studies constitute the first steps toward establishing standard procedures for an OPV lifetime characterization.

3D Printer Based Slot-Die Coater as a Lab-to-Fab Translation Tool for Solution-Processed Solar Cells[edit | edit source]

Abstract

Solution-processed solar cells continue to show great promise as a disruptive energy generation technology due to their inherently low manufacturing costs and increasing effi ciencies. [ 1–3 ] In this communication, we report the use of a 3D printer platform as a fabrication tool for solution-processed solar cells. This scalable, easily transferable coating process was used to make devices of different sizes and structures toward the aim of advancing the large-scale development of solution-processed solar cells. Organic bulk heterojunction (BHJ) and perovskitebased devices are both examples of solution-processed solar cells that can be made at low temperature, from solution and onto fl exible substrates. Recent advances in material and device structure development have seen lab-scale device power conversion effi ciencies (PCEs) approach those of more established solar technologies. For BHJ devices, the highest power conversion effi ciency reported in the open, peer-reviewed literature is over 9% [ 4 ] while a value of 11.1% has been reported for a device based on an undisclosed structure. [ 5 ] The earliest reports of organolead halide perovskite-based solar cells used a dye sensitized solar cell (DSSC) confi guration which requires a sintered TiO 2 particle layer. [6,7] The PCE of devices using mesoporousbased structures have been rapidly increasing. A record effi ciency of 19.3% has been reported very recently. [ 8 ] Perovskite-based devices without mesoporous TiO 2 structure have also been developed recently. It is reported that over 15% PCE can be achieved via a low temperature, solution-based process

A stability study of roll-to-roll processed organic photovoltaic modules containing a polymeric electron-selective layer[edit | edit source]

Abstract

The stability of roll-to-roll processed organic photovoltaic modules having an inverted structure and incorporating polyethylenimine–ethoxylate (PEIE) as the electron-selective layer was investigated. Large-area modules were fabricated on ITO-coated PET substrates using roll-to-roll coating and printing methods. Modules were encapsulated with commercially-available ultra-high gas/vapor barrier films by employing new encapsulation protocols developed during this work. The operational lifetime of modules on storage in an environmental chamber at ambient temperature and relative humidity of 35 °C and 50%, respectively, and under continuous simulated AM1.5G illumination was found to increase by more than three orders of magnitude upon encapsulation. The chemical stability of the PEIE films under these storage conditions was also studied. Fracture tests were conducted on modules exposed to the same storage conditions to investigate the effects on inter- and intra-layer adhesion and cohesion. An increase in adhesive strength was found for the exposed devices indicating an absence of any substantial mechanical degradation of the deposited layers for the exposure conditions used during this work. The results described here demonstrate the potential utility of commercially-available PEIE as a convenient and effective organic electron-selective layer for the fabrication of durable roll-to-roll processed organic solar cell devices.

Reverse gravure coating for roll-to-roll production of organic photovoltaics[edit | edit source]

Abstract

Reverse gravure (RG) coating is reported here as an alternate film deposition method for potential large scale roll-to-roll production of organic photovoltaic devices (OPVs). The basic working principles of RG coating are shown and compared to the more well-known gravure printing. Gravure printing is similar to RG coating from a process point of view, but the films produced using each method are very different to each other. An optical thickness measurement system was developed and used to monitor film thickness variation of RG coated photo-active layers with various coating parameters in situ in the roll-to-roll process. Partially and fully printed OPV modules were fabricated using, primarily, the roll-to-roll RG coating process and devices showed 2.1% and 1.5% power conversion efficiencies, respectively.

Back-Contacted Hybrid Organic-Inorganic Perovskite Solar Cells[edit | edit source]

Abstract

A novel architecture for quasi-interdigitated electrodes (QIDEs) allows for the fabrication of back-contacted perovskite solar cells. The devices showed a stable power output of 3.2%. The design of the QIDEs avoids the defects that cause short-circuiting in conventional IDEs, while enhancing the collection area of the electrodes. Photoluminescence and photocurrent mapping is used to probe the charge generation and transport properties of the perovskite solar cells.

Photonic Sintering of Copper through the Controlled Reduction of Printed CuO Nanocrystals[edit | edit source]

Abstract

The ability to control chemical reactions using ultrafast light exposure has the potential to dramatically advance materials and their processing toward device integration. In this study, we show how intense pulsed light (IPL) can be used to trigger and modulate the chemical transformations of printed copper oxide features into metallic copper. By varying the energy of the IPL, CuO films deposited from nanocrystal inks can be reduced to metallic Cu via a Cu2O intermediate using single light flashes of 2 ms duration. Moreover, the morphological transformation from isolated Cu nanoparticles to fully sintered Cu films can also be controlled by selecting the appropriate light intensity. The control over such transformations enables for the fabrication of sintered Cu electrodes that show excellent electrical and mechanical properties, good environmental stability, and applications in a variety of flexible devices.

Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells[edit | edit source]

Abstract

We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%.

Polymer solar cell modules prepared using roll-to-roll methods: Knife-over-edge coating, slot-die coating and screen printing[edit | edit source]

Papers Found[edit | edit source]

Review Articles Group 1[edit | edit source]

Perovskite solar cells: an emerging photovoltaic technology[edit | edit source]

• Article includes history of Perovskite technology
• The ABX3 structure is discussed. (X=O,C,N,halogen) X anion is most effective as a halogen. Emphasis on the B cation octahedral and A cation cubo-octahedral structure.
• Carrier diffusion lengths found to be greater than one micron for both electrons and holes.
• A architecture of FTO/bl-TiO2/MAPbI3/Au resulted in a PCE of 8%. Devoid of a mesopourous TiO2 layer and HTM. (MA = CH3NH3)
• A mixed halide perovskite (MAPbI3-xBrx) (x=0-3) appeared more stable in moisture. Br is suspected to stabilize the Ch3NH3+ cation in the lattice.
• A mixed halide perovskite (I,Br,Cl) would also allow the tuning of the band gap for greater light absorption.

progress and future perspectives for organic/inorganic perovskite solar cells[edit | edit source]

• In general: iodides cause a smaller bandgap and longer wavelength light emission, while bromides cause a higher bandgap and shorter wavelength light emission.
• MAPb₃ has a bandgap of 1.55eV, optimum is about 1.4eV
• The compact TiO₂ layer is needed for collecting the generated electrons and blocking holes.
• Because the Al₂O₃ conduction band is higher than the absorber's LUMO, no electron injection from the perovskite takes place, indicating that the electron transport occurs within the perovskite itself.
• MAPbI₃ has a high extinction coefficient, which ensures a good absorption of light at low mesoporous film thickness
• the crystallizing nature of perovskite upon deposition is important for both conductivity and charge generation since the crystallinity determines the distribution of energetic states.
• Used archetecture: Glass/FTO/TiO₂-bl/Al₂O₃ scafold/MAPbI₃/Spiro-OMeTAD/metal contact resulted in a PCE of 10.9%
• TiO₂/CH₃NH₃PbI₃/Au contact resulted in a PCE of 5.5%

The light and shade of perovskite solar cells[edit | edit source]

• Abstract: The rise of metal halide perovskites as light harvesters has stunned the photovoltaic community. As the efficiency race continues, questions on the control of the performance of perovskite solar cells and on its characterization are being addressed.

[Organolead halide perovskite: A rising player in high-efficiency solar cells][edit | edit source]

• Abstract: This perspective presents a brief description of organolead halide perovskite-based solar cells, including the structures and fundamental properties of perovskite, classifications of solar cells, and outlook of their potentials as subcells of tandem photovoltaic devices and large scale applicability.

Trend of Perovskite Solar Cells: Dig Deeper to Build Higher[edit | edit source]

• single-junction PSC reached Certified 20.1% PCE.
• controlling nucleation and grain growth may provide a more compact and uniform perovskite layer.
• Cl addition adds blue-shifted luminescence and band gap control. (multiple halides term it a wide band-gap cell)
• A hysteresis-free J-V curve can be performed at either very slow or very fast scan rates. Hysteresis during J-V measurements can lead to false PCE values. Additionally, stabilized output at max power should be checked.
• large stability issue for MAPbI₃ as in the precence of water it will decompose into PbI₂ and CH₃NH₃I. In the dark it forms a hydrate: MA₄PbI₆·2H₂O. However, this stability can be mitigated by using a mixed halide design (doping the perovskite with Br and Cl).

A brief history of perovskite materials for photovoltaic applications[edit | edit source]

Source and Full Text: 1. P. Gao, M. Grätzel, and M. K. Nazeeruddin, "Organohalide lead perovskites for photovoltaic applications", Energy & Environmental Science. 7, pp. 2448, (2014)..

Abstract

There are only few semiconducting materials that have been shaping the progress of third generation photovoltaic cells as much as perovskites. Although they are deceivingly simple in structure, the archetypal AMX3-type perovskites have built-in potential for complex and surprising discoveries. Since 2009, a small and somewhat exotic class of perovskites, which are quite different from the common rock-solid oxide perovskite, have turned over a new leaf in solar cell research. Highlighted as one of the major scientific breakthroughs of the year 2013, the power conversion efficiency of the title compound hybrid organic–inorganic perovskite has now exceeded 18%, making it competitive with thin-film PV technology. In this minireview, a brief history of perovskite materials for photovoltaic applications is reported, the current state-of-the-art is distilled and the basic working mechanisms have been discussed. By analyzing the attainable photocurrent and photovoltage, realizing perovskite solar cells with 20% efficiency for a single junction, and 30% for a tandem configuration on a c-Si solar cell would be realistic.

Focused Papers-Solar Cell Group 1[edit | edit source]

Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells[edit | edit source]

Source and Text through ILLiad Interlibrary Loan: Nam Joong Jeon,Jun Hong Noh,Young Chan Kim,Woon Seok Yang,Seungchan Ryu & Sang Il Seok,"Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells", Nature Materials 13, pp. 897–903, (2014).

• Abstract: Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH3NH3 Pb(I1 − xBrx)3 (x = 0.1–0.15) as the absorbing layer and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of γ-butyrolactone and dimethylsulphoxide ( DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH3NH3I–PbI2–DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power-conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly efficient perovskite solar cells.

High efficiency CH3NH3PbI(3−x)Clx perovskite solar cells with poly(3-hexylthiophene) hole transport layer[edit | edit source]

Source and Full Text: Francesco Di Giacomo, Stefano Razza, Fabio Matteocci, Alessandra D'Epifanio, Silvia Licoccia, Thomas M. Brown, Aldo Di Carlo,"High efficiency CH3NH3PbI(3−x)Clx perovskite solar cells with poly(3-hexylthiophene) hole transport layer", Journal of Power Sources 251, pp. 152–156, (2014).

• Not useful for this project. Organic HTMs are have very poor stability. They tend to absorb moisture and allow the perovskite itself to come into contact with moisture which leads to degradation of the cell. PCE significantly diminishes.

Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells[edit | edit source]

Source and Text through ILLiad Interlibrary Loan: Xiaomeng Wang, Yanling Fang, Lei He, Qi Wang, Tao Wu,"Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells", Materials Science in Semiconductor Processing 27, pp. 569-576, (2014).

• Abstract: A series of perovskite-based solar cells were fabricated wherein a compact layer (CL) of TiO2 of varying thickness (0–390 nm) was introduced by spray pyrolysis deposition between fluorine-doped tin oxide (FTO) electrode and TiO2 nanoparticle layer in perovskite-based solar cells. Investigations of the CL thickness-dependent current density–voltage (J–V) characteristics, dark current, and open circuit voltage (Voc) decays showed a similar trend for thickness dependence. A CL thickness of 90 nm afforded the perovskite-based solar cell with the maximum power conversion efficiency (η, 3.17%). Furthermore, two additional devices, perovskite-based solar cell omitting hole transporting materials layer and cell without the TiO2 nanoparticles, were designed and fabricated to study the influence of the CL thickness on different electron transport paths in perovskite-based solar cells. Solar cells devoid of TiO2 nanoparticles, but with perovskite and organic hole-transport materials (HTMs), exhibited sustained improvement in photovoltaic performances with increase in the thickness of CL, which is in contrast to the behavior of classical perovskite-based solar cell and common solid state solar cell which showed optimal photovoltaic performances when the thickness of CL is 90 nm. These observations suggested that TiO2 nanoparticles play a significant role in electron transport in perovskite-based solar cells.

Gas-assisted preparation of lead iodide perovskite films consisting of a monolayer of single crystalline grains for high efficiency planar solar cells[edit | edit source]

Source and Text through ILLiad Interlibrary Loan: Fuzhi Huang, Yasmina Dkhissi, Wenchao Huang, Manda Xiao, Iacopo Benesperi, Sergey Rubanov, Ye Zhu, Xiongfeng Lin, Liangcong Jiang, Yecheng Zhou, Angus Gray-Weale, Joanne Etheridge, Christopher R. McNeill, Rachel A. Caruso, Udo Bacha, Leone Spiccia, Yi-Bing Cheng,"Gas-assisted preparation of lead iodide perovskite films consisting of a monolayer of single crystalline grains for high efficiency planar solar cells", Nano Energy 10, pp. 10-18, (2014).

• Not useful for this project.

Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells[edit | edit source]

Source and Full Text: Yixin Zhao and Kai Zhu,"Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells", J. Phys. Chem. Lett. 4, pp. 2880–2884, (2013).

• Abstract: We report on the effect of TiO2 film thickness on the charge transport, recombination, and device characteristics of perovskite (CH3NH3)PbI3 sensitized solar cells using iodide-based electrolytes. (CH3NH3)PbI3 is relatively stable in a nonpolar solvent (e.g., ethyl acetate) with a low iodide concentration (e.g., 80 mM). Frequency-resolved modulated photocurrent/photovoltage spectroscopies show that increasing TiO2 film thickness from 1.8 to 8.3 μm has little effect on transport but increases recombination by more than 10-fold, reducing the electron diffusion length from 16.9 to 5.5 μm, which can be explained by the higher degree of iodide depletion within the TiO2 pores for thicker films. The changes of the charge-collection and light-absorption properties of (CH3NH3)PbI3 sensitized cells with varying TiO2 film thickness strongly affect the photocurrent density, photovoltage, fill factor, and solar conversion efficiency. Developing alternative, compatible redox electrolytes is important for (CH3NH3)PbI3 or similar perovskites to be used for potential photoelectrochemical applications.

Optical bleaching of perovskite (CH3NH3)PbI3 through room-temperature phase transformation induced by ammonia[edit | edit source]

Source and Full Text: Yixin Zhao and Kai Zhu,"Optical bleaching of perovskite (CH3NH3)PbI3 through room-temperature phase transformation induced by ammonia", Chemical Communications 13, pp. 1605-1607, (2014).

• Not useful for this project

Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length[edit | edit source]

Source and Full Text: Yixin Zhao, Alexandre M. Nardes, and Kai Zhu,"Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length", J. Phys. Chem. Lett. 5, pp. 490–494, (2014).

• Abstract: We report on the effect of TiO2 film thickness on charge transport and recombination in solid-state mesostructured perovskite CH3NH3PbI3 (via one-step coating) solar cells using spiro-MeOTAD as the hole conductor. Intensity-modulated

photocurrent/photovoltage spectroscopies show that the transport and recombination properties of solid-state mesostructured perovskite solar cells are similar to those of solidstate dye-sensitized solar cells. Charge transport in perovskite cells is dominated by electron conduction within the mesoporous TiO2 network rather than from the perovskite layer. Although no significant film-thickness dependence is found for transport and recombination, the efficiency of perovskite cells increases with TiO2 film thickness from 240 nm to about 650−850 nm owing primarily to the enhanced light harvesting. Further increasing film thickness reduces cell efficiency associated with decreased fill factor or photocurrent density. The electron diffusion length in mesostructured perovskite cells is longer than 1 μm for over four orders of magnitude of light intensity.

Low-Temperature and Solution-Processed Amorphous WOX as Electron-Selective Layer for Perovskite Solar Cells[edit | edit source]

Source and Full Text: Kai Wang, Yantao Shi, Qingshun Dong, Yu Li, Shufeng Wang, Xufeng Yu, Mengyao Wu, and Tingli Ma,"Low-Temperature and Solution-Processed Amorphous WOX as Electron-Selective Layer for Perovskite Solar Cells", J. Phys. Chem. Lett. 6, pp. 755–759, (2015).

• Study demonstrates WOx is an alternative to TiO2 for the ETM material.

Crystal Morphologies of Organolead Trihalide in Mesoscopic/Planar Perovskite Solar Cells[edit | edit source]

Source and Full Text: Yuanyuan Zhou, Alexander L. Vasiliev, Wenwen Wu, Mengjin Yang, Shuping Pang, Kai Zhu, and Nitin P. Padture,"Crystal Morphologies of Organolead Trihalide in Mesoscopic/Planar Perovskite Solar Cells", J. Phys. Chem. Lett. 6, pp. 2292–2297, (2015).

• Abstract: The crystal morphology of organolead trihalide perovskite (OTP) light absorbers can have profound influence on the perovskite solar cells (PSCs) performance. Here we have used a combination of conventional transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), in cross-section and plan-view, to characterize the morphologies of a solution-processed OTP (CH3NH3PbI3 or MAPbI3) within mesoporous TiO2 scaffolds and within capping and planar layers. Studies of TEM specimens prepared with and without the use of focused ion beam (FIB) show that FIBing is a viable method for preparing TEM specimens. HRTEM studies, in conjunction with quantitative X-ray diffraction, show that MAPbI3 perovskite within mesoporous TiO2 scaffold has equiaxed grains of size 10–20 nm and relatively low crystallinity. In contrast, the grain size of MAPbI3 perovskite in the capping and the planar layers can be larger than 100 nm in our PSCs, and the grains can be elongated and textured, with relatively high crystallinity. The observed differences in the performance of planar and mesoscopic-planar hybrid PSCs can be attributed in part to the striking differences in their perovskite-grain morphologies.

Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode[edit | edit source]

Source and Full Text: Huawei Zhou, Yantao Shi, Qingshun Dong, Hong Zhang, Yujin Xing, Kai Wang, Yi Du, and Tingli Ma,"Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode", J. Phys. Chem. Lett. 5, pp. 3241–3246, (2014).

• Abstract: Low cost, high efficiency, and stability are straightforward research challenges in the development of organic–inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.

Review Articles Group 2[edit | edit source]

Advancements in all-solid-state hybrid solar cells based on organometal halide perovskites[edit | edit source]

Source and Full Text: Shaowei Shi, Yongfang Li, Xiaoyu Li, and Haiqiao Wang, "Advancements in all-solid-state hybrid solar cells based on organometal halide perovskites", Material horizons 2 pp. 378-405, (2015).

• Very useful review article. Includes various up to date deposition methods for PSCs.
• Perovskites can act as a light absorber as well as a bipolar transport of both holes and electrons.
• In depth description of benefits of potential device architectures for PSCs.
  • Mesoporous metal oxide n-type layers like TiO2. FTO/bl-TiO2/mp-TiO2(rutile)/MAPbX3/spiro-MeOTAD/Au (X=I,Br,Cl)
  • Meso-superstructured designs using Al2O3. FTO/bl-TiO2/mp-Al2O3/MAPbX3/spiro-MeOTAD/Ag (X=I,Br,Cl)
• Various HTMs are discussed, Spiro-MeOTAD so far contributes to the highest PCE, however, P3HT, and PTAA are viable polymer based HTMs.
• Main limiting factor for practical application is the sensitivity to moisture and elevated temperature.

Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells[edit | edit source]

Source and Full Text: Yixin Zhao and Kai Zhu,"Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells", J. Phys. Chem. Lett. 5, pp. 4175–4186, (2014).

• Abstract: Organic and inorganic hybrid perovskites (e.g., CH3NH3PbI3) have emerged as a revolutionary class of light-absorbing semiconductors that has demonstrated a rapid increase in efficiency within a few years of active research. Controlling perovskite morphology and composition has been found critical to developing high-performance perovskite solar cells. The recent development of solution chemistry engineering has led to fabrication of greater than 15–17%-efficiency solar cells by multiple groups, with the highest certified 17.9% efficiency that has significantly surpassed the best-reported perovskite solar cell by vapor-phase growth. In this Perspective, we review recent progress on solution chemistry engineering processes and various control parameters that are critical to the success of solution growth of high-quality perovskite films. We discuss the importance of understanding the impact of solution-processing parameters and perovskite film architectures on the fundamental charge carrier dynamics in perovskite solar cells. The cost and stability issues of perovskite solar cells will also be discussed.

Review of recent progress in chemical stability of perovskite solar cells[edit | edit source]

Source and Full Text: Guangda Niu, Xudong Guo and Liduo Wang,"Review of recent progress in chemical stability of perovskite solar cells", J. Mater. Chem. 3(17), (2014).

• Perovskites: ease of fabriaction, small band-gap, high extinction coefficients, and high carrier mobility - Thin film
• Record PCE is 20.1%
• Power conversion efficiency(has been main focus) and device stability(future direction) are largest issues currently
• PCSs are susceptible to: Oxygen+moisture, UV light, the solution process(solvents, solutes, additives), and temperature.
• CH3NH3PbI3 started to decompose at a humidity of 55%, dark brown -> yellow
• CH3NH3Pb(I1-xBrx)3 (x = 0.2, 0.29) exhibits improved stability. (vs moisture, solutions, and temperature)
• This paper deals with organic HTM/no HTM(no HTM yeilded 10.5% PCE) layers.
  • This paper is useful for understanding stability although my direction is using inorganic HTM layers which prevents many of the issues discussed here.

Focused Papers-Solar Cell Group 2[edit | edit source]

Summaries to be added

Efficient organic–inorganic hybrid perovskite solar cells processed in air[edit | edit source]

Study on the stability of CH3NH3PbI3 films and the effect of post-modification by aluminum oxide in all-solid-state hybrid solar cells[edit | edit source]

Sub-150C processed meso-superstructured perovskite solar cells with enhanced efficiency[edit | edit source]

Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates[edit | edit source]

Carbon Nanotube/Polymer Composites as a Highly Stable Hole Collection Layer in Perovskite Solar Cells[edit | edit source]

Source: Habisreutinger SN, Leijtens T, Eperon GE, Stranks SD, Nicholas RJ, Snaith HJ. "Carbon Nanotube/Polymer Composites as a Highly Stable Hole Collection Layer in Perovskite Solar Cells" Nano Lett. 2014 Oct 8;14(10):5561–8.

Efficient planar heterojunction perovskite solar cells by vapour deposition[edit | edit source]

Environmentally responsible fabrication of efficient perovskite solar cells from recycled car batteries[edit | edit source]

• Process is described as thus:

1. Harvest material from the anodes and cathodes of car battery
2. Synthesize PbI2 from the collected materials
3. Deposite lead iodide perovskite nanocrystals

• XRD and PL response are shown to be near equivalent for PSCs fabriacated from both car batteries and high purity commercial PbI2

Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells[edit | edit source]

New Physical Deposition Approach for Low Cost Inorganic Hole Transport Layer in Normal Architecture of Durable Perovskite Solar Cells[edit | edit source]

• This work focused on fabrication of all inorganic hole and electron transport materials based perovskite solar cells
• Durable perovskite solar cells with stable efficiency up to 60 days reported is achieved.
• The rotational angular Sputtering technique introduced as a sufficient method in deposition of inorganic ETM or HTMs on perovskite layers
• Well-coverage deposition of NiO (nickel oxide) layer on perovskite layer successful conducted
• This method introduced as an appropriate method in deposition of NiO on perovskite layers even containing pinholes in perovskite layers.

Metal/Metal-Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO3[edit | edit source]

Small Photocarrier Effective Masses Featuring Ambipolar Transport in Methylammonium Lead Iodide Perovskite: A Density Functional Analysis[edit | edit source]

Comparison of transparent conductive indium tin oxide, titanium-doped indium oxide, and fluorine-doped tin oxide films for dye-sensitized solar cell application[edit | edit source]

Screening procedure for structurally and electronically matched contact layers for high-performance solar cells: hybrid perovskites[edit | edit source]

Research improves efficiency from larger perovskite solar cells[edit | edit source]

Focused Papers-3D Printing[edit | edit source]

Open-Source Syringe Pump Library[edit | edit source]

Combining 3D printing and liquid handling to produce user-friendly reactionware for chemical synthesis and purification[edit | edit source]

PV Nano Cell's NanoMetal Inks Write Up 2016 as the Year of 3D Printed Electronics[edit | edit source]

Source and Text: Davide,"PV Nano Cell's NanoMetal Inks Write Up 2016 as the Year of 3D Printed Electronics", News, 3D Printing (2016).

• 3D printed electronics, both for prototyping of PCBs and end use wearable and IoT products
• silver and copper based single crystal nano-metric conductive inks
• Impact: 3D print electronic-capable products -> such as photovoltaics and printed circuit boards
• competitive Low cost 1/3 of other inks on market
• PVN has a production capacity of hundreds of kilograms and is specifically targeting the market for mass end-use products and parts.