Journal Article 2D polymers 2D transition metal disulfides MoS2 WS2 cation exchange conjugated polymer electrical conductivity electron affinity electron-selective contacts heterojunctions hole transport layers in situ electrochemical resonant Raman spectroscopy liquid exfoliation nonfullerene organic solar cells n‐type doping organic electrochemical transistors organic semiconductors organic solar cells passivating contacts photocatalysis semiconducting polymers silicon solar cells solar fuels time‐resolved spectroelectrochemistry titanium oxynitride