摘要
Conventional organic solar cells are based on fullerene acceptors,which caused several drawbacks including poor absorption in visible and near IR regions,limited tunability of energy levels,and most importantly,large voltage loss from the optical bandgap of the cell to the open circuit voltage of the solar cell[1].During the past few years,nonfullerene OSCs have emerged as a promising alternative to fullerene devices,as their optical and electronic properties can be readily tuned.Furthermore,it has been demonstrated in numerous cases that non-fullerene OSCs[2]can achieve small voltage loss of about 0.55 V,which is much improved compared to that of conventional devices.Achieving such a small voltage loss is of paramount importance to OSCs,as it indicates the maximum achievable efficiency of OSCs can be increased to nearly 20%.
