Thin-film photovoltaics based on alkylammonium lead iodide perovskite light absorbers have recently emerged as a promising low-cost solar energy harvesting technology. To date, the perovskite layer in these efficient solar cells has generally been fabricated by either vapor deposition or a two-step sequential deposition process. We report that flat, uniform thin films of this material can be deposited by a one-step, solvent-induced, fast crystallization method involving spin-coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. Analysis of the devices and films revealed that the perovskite films consist of large crystalline grains with sizes up to microns. Planar heterojunction solar cells constructed with these solution-processed thin films yielded an average power conversion efficiency of 13.9±0.7% and a steady state efficiency of 13% under standard AM 1.5 conditions.

Thin‐film photovoltaics based on alkylammonium lead iodide perovskite light absorbers have recently emerged as a promising low‐cost solar energy harvesting technology. To date, the perovskite layer in these efficient solar cells has generally been fabricated by either vapor deposition or a two‐step sequential deposition process. We report that flat, uniform thin films of this material can be deposited by a one‐step, solvent‐induced, fast crystallization method involving spin‐coating of a DMF solution of CH3NH3PbI3 followed immediately by exposure to chlorobenzene to induce crystallization. Analysis of the devices and films revealed that the perovskite films consist of large crystalline grains with sizes up to microns. Planar heterojunction solar cells constructed with these solution‐processed thin films yielded an average power conversion efficiency of 13.9±0.7 % and a steady state efficiency of 13 % under standard AM 1.5 conditions.

Band-like charge transport is observed in lead halide perovskite field-effect transistors.

No abstract

Upscaling efficient and stable perovskite layers is one of the most challenging issues in the commercialization of perovskite solar cells. Here, a lead halide–templated crystallization strategy is developed for printing formamidinium (FA)–cesium (Cs) lead triiodide perovskite films. High-quality large-area films are achieved through controlled nucleation and growth of a lead halide•N-methyl-2-pyrrolidone adduct that can react in situ with embedded FAI/CsI to directly form α-phase perovskite, sidestepping the phase transformation from δ-phase. A nonencapsulated device with 23% efficiency and excellent long-term thermal stability (at 85°C) in ambient air (~80% efficiency retention after 500 hours) is achieved with further addition of potassium hexafluorophosphate. The slot die–printed minimodules achieve champion efficiencies of 20.42% (certified efficiency 19.3%) and 19.54% with an active area of 17.1 and 65.0 square centimeters, respectively.