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

[Display omitted] • Fluorescence Resonance Energy Transfer from P3HT to CuInSe 2. • Analytical study of the absorption and emission spectra of P3HT:CuInSe 2 composites. • Förster distance of critical energy transfer is estimated as 3.61 nm. • The average distance between donor–acceptor is found to be 4.71 nm. • Analysis of resonance charge transfer by estimation of HOMO-LUMO energy of donor–acceptor. This letter reports the paramount fluorescence resonance energy transfer mechanism for photo induced charge transfer from P3HT to solvothermally derived CuInSe 2. The HOMO (-4.85 eV) and LUMO (-3.38 eV) energy states of CuInSe 2 (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:CuInSe 2) demonstrates possibility of successful charge transfer. Stern–Volmer analysis of absorption and emission spectroscopy ensures static energy quenching phenomena. The Förster 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 CuInSe 2. [ABSTRACT FROM AUTHOR]