An experimental approach to ensure energy quenching and fluorescence resonance energy transfer of excitons from P3HT to CuInSe2

This letter reports the paramount fluorescence resonance energy transfer mechanism for photo induced charge transfer from P3HT to solvothermally derived CuInSe2. The HOMO (-4.85 eV) and LUMO (-3.38 eV) energy states of CuInSe2 (electrical conductivity = 1.1x 10(-7) Scm(-1)) are determined from cyclic voltammetry and optical study. This HOMO-LUMO position agrees to select P3HT polymer as possible donor of excitons. Steady-state luminescence study of composite (P3HT:CuInSe2) demonstrates possibility of successful charge transfer. Stern-Volmer analysis of absorption and emission spectroscopy ensures static energy quenching phenomena. The Forster distance (R-0) of critical energy transfer is estimated as 3.61 nm. The average distance between donor-acceptor (r(avg) = 4.71 nm) is<8 nm and within the range 0.5R(0) < r < 1.5R(0) (1.81 nm < r < 5.42 nm), which ensures energy transfer from P3HT to CuInSe2.