Loukeris Georgios, Baretzky Clemens, Bogachuk Dmitry, Gillen Audrey Elizabeth, Yang Bowen, Suo Jiajia, Kaiser Waldemar, Mosconi Edoardo, De Angelis Filippo, Boschloo Gerrit, Bett Andreas Walter, Würfel Uli, Kohlstädt Markus
Fraunhofer Institute für Solar Energy Systems ISE, 79110, Freiburg im Breisgau, Germany.
Materials Research Center FMF, University of Freiburg, 79104, Freiburg im Breisgau, Germany.
Chemphyschem. 2025 Aug 4;26(15):e202500022. doi: 10.1002/cphc.202500022. Epub 2025 Apr 17.
All-perovskite tandem solar cells are emerging at a fast rate because of their potential to exceed efficiencies of Si-perovskite tandems, in combination with faster manufacturing, lower cost, and the ability to be processed on flexible substrates. Mixing halides is a key to achieve wide-bandgap absorbers, which however suffer from halide segregation under illumination, resulting in lowering of the bandgap. To tackle this problem, butylamine (BA) has been added to the perovskite precursor solution and is found to react with the formamidinium (FA) cation, producing N-butylformamidinium (BuFA), which accumulates at the perovskite surface and grain boundaries. The creation of the BuFA cation results in suppressed halide segregation and improved crystallization. Density functional theory calculations propose the reduction of halide defect formation upon the addition of BA, being a key to stabilize mixed-halide perovskites. Lastly, we observe a more stable performance of single junction p-i-n perovskite solar cells with the addition of BA under constant illumination at 65 °C.
全钙钛矿串联太阳能电池正迅速兴起，因为它们有可能超越硅-钙钛矿串联电池的效率，同时具备更快的制造速度、更低的成本以及可在柔性基板上加工的能力。混合卤化物是实现宽带隙吸收体的关键，但在光照下会出现卤化物偏析，导致带隙降低。为了解决这个问题，已将丁胺（BA）添加到钙钛矿前驱体溶液中，发现它与甲脒（FA）阳离子反应，生成N-丁基甲脒（BuFA），BuFA在钙钛矿表面和晶界处积累。BuFA阳离子的产生抑制了卤化物偏析并改善了结晶。密度泛函理论计算表明，添加BA后卤化物缺陷形成减少，这是稳定混合卤化物钙钛矿的关键。最后，我们观察到在65°C恒定光照下添加BA的单结p-i-n钙钛矿太阳能电池具有更稳定的性能。
