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In recent years, perovskite solar cells have achieved high efficiency in small areas, but the industrialization of perovskite solar cells is still hampered by the efficiency loss of cells during area scaling. Series modules are currently the most widely used and effective modular process for perovskite solar cells, a process that requires the patterning of the layer stack in individual cells. This interconnection scheme consists of three lines, P1–P3, which are ablated using a pulsed laser beam. In this work, we developed an efficient perovskite module with a high geometric fill factor (GFF) based on a two-step spin-coating method by optimizing the laser ablation step. We constructed the entire device structure by means of a picosecond green pulsed laser, meanwhile, the dead area is greatly reduced by optimizing the parameters and process, and finally achieving an ultra-high GFF of over 99%. In addition, we investigated the effect of poor P2 and P3 ablation on the perovskite solar modules and compared the performance of the module before and after ablation optimization. We finally obtained a maximum photoelectric conversion efficiency of 22.79% with an aperture area of 12.6 cm2. Concurrently, we conducted electrocatalytic hydrogen production experiments on the prepared perovskite solar modules, and the experimental results have also shown excellent performance and good prospects. [ABSTRACT FROM AUTHOR]

A precursor film with a Cu gradient was prepared in order to improve the quality of the absorber film produced by sputtering CIGS targets when using glass substrates. Two ceramic quaternary targets with different copper content were used for alternatively sputtering to get a bi-layer precursor film with a Cu gradient; meanwhile, the crystallization property and cell performance were studied. This was done in order to study the activities of the Cu element in the precursor layer before and after selenization. The film states of the temperature-rise period and high temperature selenization period were investigated. The appropriate structure of the precursor film was the Cu-rich layer underneath the Cu-poor layer. The Cu–Se phase, which is important for the crystalline property, can be produced in the Cu-rich layer under the heating period. The Cu-poor layer on the top reacts with the Cu-Se compound in the annealing process at a high temperature, and the big grain size of the absorber layer can be obtained due to Cu diffusion promoted by the gradient in the precursor film, as well as better conversion efficiency. This result shows that constructing the precursor film with a Cu gradient by sputtering different quaternary CIGS targets is a very promising fabrication method to obtain high-performance solar-cell devices with a good crystallization property under an annealing temperature of 550 °C and is suitable for further industrialized application. [ABSTRACT FROM AUTHOR]

Metal hybrid halide perovskite solar cells (PSCs) are very sensitive to air, and it is challenging to obtain air-processed, air-stable, and highly crystalline perovskite films. Photovoltaic performance decays dramatically due to air humidity influence with power conversion efficiency (PCE) of most air-processed PSCs < 15%. In this work, we develop a facile method to air-processed, highly crystalline (MA0.2FA0.8PbI3)1.0(CsPbBr3)0.05 perovskite films in ambient air with large grain size and low trap density based on mix-cation single crystal engineering. This method shows 75% increase in grain size and 28% decrease in trap density than conventional molecule/ion solution mixing-processed method. The large grain, low trap density, andhigh crystalline perovskite films result in high-efficient and air-stable PSCs. Consequently, the PCE increases to 36.7% from 12.56% for conventional molecule/ion solution mixing-processed devices and to 17.17% for single crystal engineering-based ones. Furthermore, benefiting from high moisture resistance of mix-cation single crystal engineering-based films, the PSC air stability has been improved significantly and 72% of the initial performance retains after 40 days of storage in ambient environment with a relative humidity of 60% at 25 °C without any encapsulation, with a 26% slower degradation rate than conventional solution-mixing method. [ABSTRACT FROM AUTHOR]

High-performance perovskite solar cell processed in ambient air is a big challenge due to the sensitivity of perovskite films to air. Many defects are generated easily at grain boundaries and in the perovskite films by conventional molecular/ion precursor solution mixing methods (i.e., solution mixing-based method), which restrict its stability in air and photovoltaic performance with most power conversion efficiency less than 15%. In this work, we develop a facile method for air-processed, highly crystalline, quasi-3D perovskite film with large grain size (over 6.6 times bigger than that from control conventional method) and improved ambient air stability by phenylethylammonium (PEA)-doped MA1−xPEAxPbI3 perovskite crystal engineering. Furthermore, benefiting from PEA+ doping and crystal engineering, the trap density decreases 50% compared with control. Consequently, with the optimal concentration of PEA doping, the power conversion efficiency increases from 15.6% for conventional solution mixing-based perovskite solar cells to 17.6% for crystal engineering-based ones with significantly improved moisture stability. The perovskite crystal engineering-based solar cells without any encapsulation retain 75% of the initial performance after 30-day storage in ambient air under a relative humidity of 50 ± 10%, and two times faster degradation rate is observed for control, conventional solution mixing-based perovskite solar cells when compared with crystal engineering-based ones. [ABSTRACT FROM AUTHOR]

• A simple solvent engineering strategy was employed to control morphology of PbI 2 films effectively by water processing. • Platelet-like PbI 2 films can successfully control the residual amount of PbI 2 in perovskite film. • Platelet-like PbI 2 films can control the morphology of the perovskite film and improve the device efficiency [Display omitted] The performance of organic-inorganic perovskite solar cells depends largely on the quality of perovskite film. Currently, various methods are applied to prepare the perovskite film. Among them, the two-step method is counted as a promising candidate to obtain high-quality perovskite film. In this study, we attain a special platelet-like PbI 2 films by applying pure water to cover wet PbI 2 film and standing for a period of time. The unique morphology contributes to the entry of organic cations solution into the PbI 2 and promoting its reaction with PbI 2 , which reducing the residual amount of PbI 2 in the perovskite film. Compared to the traditional two-step method, water processing method can obtain a high-quality perovskite film with enlarged grain size, improved crystallization, and prolonged carrier lifetime. As a result, the efficiency of the prepared device based on the film has increased from 17.90% without water processing to 20.14% of water processing. Which demonstrates that this solvent engineering for PbI 2 film opens up a possibility to prepare high-quality perovskite in a two-step method and obtain highly efficient perovskite solar cells. [ABSTRACT FROM AUTHOR]

Gas-quenching fabrication of perovskite films demonstrates promising compatibility for commercialization of perovskite photovoltaics. Seeking suitable ligand for the perovskite precursor inks to improve the crystalline quality of gas-quenched methylammonium free perovskite films is critical for realizing up-scalable fabrication of stable perovskite solar cells. In this work, a series of pyrrolidone-based ligands are employed in gas-quenching fabrication of FA 0.9 Cs 0.1 PbI 3 perovskite films. Optical and morphological characterizations indicate 2-pyrrolidone is the most preferred ligand to deliver a neat buried-interface as well as a light-trapping surface at the rear of the device, which maximized the light-harvesting and the photocurrent of the device. The corresponding device achieved a power conversion efficiency of 21.6% without any interfacial passivation, as well as reduced defect density from their electrical characteristics. Moreover, a more stable performance of the device is obtained with 2-pyrrolidone compared to other pyrrolidone-based ligands, demonstrating 2-pyrrolidone as a promising ligand in designing the perovskite inks for methylammonium-free perovskite solar cells. • Various pyrrolidone-based ligands are studied in gas-quenching of FA 0.9 Cs 0.1 PbI 3 films. • Bifacial optical properties of perovskite films are optimized with NP ligand. • smoother buried interface and a rougher surface contribute to enhanced light harvesting. • NP device achieved 21.6% efficiency without any interfacial passivation [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel heterogeneous lead iodide, exhibiting two (0 0 1) interplanar distances of 6.9 Å and 9.0 Å, was constructed. • The heterogeneous structure can regulate the crystallization process of PbI 2 and perovskite films. • The V OC and PCE were raised to 1.21 V and 24.24%. At present, the highest power conversion efficiency (PCE) of perovskite solar cells (PSCs) has exceeded 25%, which exhibits great potential for commercial applications. Obtaining pinhole-free, superior crystal, and high-quality perovskite films with fewer defects by adjusting the lead iodide (PbI 2) intermediate films in a two-step sequential deposition has become research arousing general interest. Herein, a heterogeneous lead iodide (HLI) structure with two (0 0 1) interplanar distances (9.0 Å and 6.9 Å), can optimize the crystallization process of perovskite to get better surface morphology and is constructed by intercalated choline chloride (a kind of vitamin B4, VB4). HLI simultaneously improves the carrier lifetime of perovskite film from 1.96 µs to 3.28 µs and reduces defect state density. Together with better morphology and lower defect state density, the open circuit voltage (V OC) and PCE based on (FAPbI 3) 0.97 (MAPbBr 3) 0.03 is significantly boosted. In addition, with double-sided modification, HLI produces an excellent PCE of 24.27% with a V OC of 1.21 V. We believe that the novel heterogeneous PbI 2 structure could be a generic method to improve the efficiency of PSCs. [ABSTRACT FROM AUTHOR]

Lead halide perovskite solar cells (PSCs) have attracted intensive attention since their power conversion efficiency (PCE) increased sharply in recent years. Thereinto, triple cation perovskite (TCP) is a popular light absorption layer for PSCs due to its excellent thermal and humidity stability. However, a large amount of MA+ (≥15%) and Br- (≥15%) in TCP makes the bandgap widen drifting from the optimum value. There is some extent of a trade-off between PCE and stability for PSCs, and narrow-bandgap TCP is one of the best choices for light absorption material to achieve an optimum balance between PCE and stability. Herein, we prepared a narrow-bandgap (1.56 eV) high-quality TCP (Cs 0.05 FA 0.86 MA 0.09 Pb(I 0.97 Br 0.03) 3) film with an average grain size up to 1208 nm and corresponding PSC with high efficiency of 20.8%. Moreover, the intermediate process of the TCP film crystallization was carefully studied disclosing the critical α-Phase intermediate and corresponding roles of DMSO solvent and MACl additive through quasi-in-situ XRD in the film formation process, and the results may give critical clues to the fabrication of high-quality narrow-bandgap TCP based PSCs. • High-quality FAPbI3-based TCP film with a narrow-bandgap (1.56 eV) was successfully prepared by applying the α-phase intermediate strategy: the grain size of the film can reach 1208 nm and the carrier lifetime exceeds 3 μs. • The crytical intermediate process introduced by the synergy of DMSO and MACl was disclosed through quasi-in-situ XRD in the film formation process. • The solar cells based on the low-doping FAPbI 3 -based TCP films show high performance and good stability even without surface passivation. [ABSTRACT FROM AUTHOR]