▲ 作者:Hao Chen, Aidan Maxwell, Chongwen Li, Sam Teale, Bin Chen, Tong Zhu, Esma Ugur, George Harrison, Luke Grater, Junke Wang, Zaiwei Wang, Lewei Zeng, So Min Park, Lei Chen, Peter Serles, Rasha Abbas Awni, Biwas Subedi, Xiaopeng Zheng, Chuanxiao Xiao, Nikolas J. Podraza, Tobin Filleter, Cheng Liu, Yi Yang, Joseph M. Luther, Edward H. Sargent
▲ 链接:
https://www.nature.com/articles/s41586-022-05541-z
▲ 摘要:
在宽带隙(超过1.7 eV)的钙钛矿太阳能电池中,开路电压(VOC)亏缺比大约1.5 eV的钙钛矿更。准费米能级分裂测量表明,在电子传输层接触处存在VOCs限制复合。
加拿大多伦多大学教授Edward Sargent团队研究发现,这源于不均匀的表面电位和较差的钙钛矿电子传输层能量排列。普通的单铵表面处理无法解决这一问题;作为一种替代方法,他们引入了二铵分子来修饰钙钛矿的表面状态,并实现了更均匀的表面电位空间分布。使用1,3-丙烷二铵,准费米级分裂提高了90 meV,使1.79 eV的钙钛矿太阳能电池具有1.33 V的VOC认证和超过19%的功率转换效率(PCE)。
将该层纳入单片全钙钛矿串联,研究者报告了2.19 V的创纪录VOC(详细平衡VOC限值的89%)和超过27%的PCE(26.3%经过准稳态认证)。这些串联在操作500小时后保留了超过86%的初始PCE。
▲ Abstract:
The open-circuit voltage (VOC) deficit in perovskite solar cells is greater in wide-bandgap (over 1.7 eV) cells than in perovskites of roughly 1.5 eV. Quasi-Fermi-level-splitting measurements show VOC-limiting recombination at the electron-transport-layer contact. This, we find, stems from inhomogeneous surface potential and poor perovskite–electron transport layer energetic alignment. Common monoammonium surface treatments fail to address this; as an alternative, we introduce diammonium molecules to modify perovskite surface states and achieve a more uniform spatial distribution of surface potential. Using 1,3-propane diammonium, quasi-Fermi-level splitting increases by 90 meV, enabling 1.79 eV perovskite solar cells with a certified 1.33 V VOC and over 19% power conversion efficiency (PCE). Incorporating this layer into a monolithic all-perovskite tandem, we report a record VOC of 2.19 V (89% of the detailed balance VOC limit) and over 27% PCE (26.3% certified quasi-steady state). These tandems retained more than 86% of their initial PCE after 500 h of operation.