Journal Article Fluorenes Polymers Polystyrenes Research Support, Non-U.S. Gov't Thiophenes carbazole cathode interlayer charge separation dual-color imaging efficiency fluorination hole transport layer hyperbranched polymer low-cost copolymer donors nonradiative recombination organic solar cells organic/perovskite photodetectors poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) polymer solar cells response speed scanning kelvin probe self‐assembled monolayer voltage loss