Journal Article all-perovskite tandem solar cells Amino Acids, Branched-Chain Research Support, Non-U.S. Gov't SnO2 QD X‐ray detection branched-chain amino acids branched-chain aminotransferase carrier concentration carrier management defect engineering defect passivation electron transfer flexible hardening effect hole transport layer-free large linear dynamic range large-scale low-bandgap perovskites low-bandgap tin-lead multiple hydrogen bonds natural variation nitrogen oxygen vacancy perovskite solar cells piezoelectric planar perovskite solar cells rice spacer conformation taurine