Tailoring component incorporation for homogenized perovskite solar cells

Deep-level traps at the buried interface of perovskite and energy mismatch problems between the perovskite layer and heterogeneous interfaces restrict the development of ideal homogenized films and efficient perovskite solar cells(PSCs)using the one-step spin-coating method.Here,we strategically employed sparingly soluble germanium iodide as a homogenized bulk in-situ reconstruction inducing material preferentially aggregated at the perovskite buried interface with gradient doping,markedly reducing deep-level traps and withstanding local lattice strain,while minimizing non-radiative recombination losses and enhancing the charge carrier lifetime over 9μs.Furthermore,this gradient doping assisted in modifying the band diagram at the buried interface into a desirable flattened alignment,substantially mitigating the energy loss of charge carriers within perovskite films and improving the carrier extraction equilibrium.As a result,the optimized device achieved a champion power conversion efficiency of 25.24% with a fill factor of up to 84.65%,and the unencapsulated device also demonstrated excellent light stability and humidity stability.This work provides a straightforward and reliable homogenization strategy of perovskite components for obtaining efficient and stable PSCs.

一种通用静电组装策略用于印刷无机纳米颗粒及其在大面积钙钛矿太阳电池中的应用

无机纳米颗粒作为一种极具前景的材料,在钙钛矿太阳电池的传输层中得到了广泛应用.然而,无机纳米颗粒易于聚集的特性阻碍了其进一步的发展.在大面积制备过程中,无机纳米颗粒的聚集加剧了“咖啡环效应”,导致薄膜不均匀,使得底部界面性能较差,进而影响钙钛矿薄膜的结晶,最终导致整个器件性能下降.为解决这一问题,我们将一种带电聚合物一一聚乙烯亚胺引入至无机纳米颗粒溶液中.聚乙烯亚胺的带电性质对无机纳米颗粒的聚集起到了显著的抑制作用,此外,添加聚乙烯亚胺还增加了无机纳米颗粒溶液的粘度,有助于减少薄膜上的负面咖啡环效应.最终,我们在基于1-cm^(2)正式结构且使用SnO_(2)传输层的器件上实现了23.2%的光电转换效率.为进一步证明这一策略的普适性,我们还将此策略验证基于NiO_(x)传输层的1-cm^(2)反式器件,其转换效率超过20%.