Table 1. Selected electronic transition energies (eV) and corresponding oscillator strengths (f), main compositions and CI coefficients of the BT: PC₆₁BM blend.

States	Transition Energy (eV)a	fb	Δr(Å)c	Excited-state Propertyd
S1	2.0506 (604.63 nm)	2.2006	0.759739	LE
S2	2.4156 (513.27 nm)	0.0024	0.598960	LE
S3	2.4404 (508.06 nm)	0.0467	0.419422	LE
S4	2.4476 (506.55 nm)	0.0000	0.753877	LE
S5	2.5183 (492.33 nm)	0.0001	3.497080	ICT
S6	2.5328 (489.52 nm)	0.0006	4.502078	ICT
S7	2.5382 (488.47 nm)	0.0006	5.387317	ICT
S8	2.5523 (485.78 nm)	0.0000	1.796438	ICT
S9	2.6739 (463.68 nm)	0.0001	0.178010	LE
S10	2.6891 (461.06 nm)	0.0001	0.569387	LE
S11	2.7191 (455.97 nm)	0.0004	0.619133	LE
S12	2.7810 (445.83 nm)	0.0000	0.505284	LE
S13	2.8326 (437.70 nm)	0.0000	0.199343	LE
S14	2.8624 (433.15 nm)	0.0009	0.665378	LE
S15	2.9473 (420.68 nm)	0.0014	0.706160	LE
S16	2.9740 (416.90 nm)	0.0013	1.097320	LE
S17	2.9945 (414.05 nm)	0.0000	0.601590	LE
S18	3.0872 (401.61 nm)	0.0003	0.777263	LE
S19	3.1032 (399.53 nm)	0.0026	0.735057	LE
S20	3.1329 (395.75 nm)	0.0025	0.794401	LE
S21	3.1703 (391.09 nm)	0.0081	0.158442	LE
S22	3.2247 (384.49 nm)	0.0200	0.719405	LE
S23	3.3056 (375.07 nm)	0.0000	7.582522	ICT
S24	3.3712 (367.78 nm)	0.0006	7.344502	ICT
S25	3.4619 (358.14 nm)	0.0012	0.338456	LE
S26	3.5109 (353.14 nm)	0.2450	0.800606	LE
S27	3.5121 (353.02 nm)	0.6954	1.791835	LE
S28	3.5327 (350.96 nm)	0.0037	1.127917	LE
S29	3.5501 (349.24 nm)	0.0005	6.733170	ICT
S30	3.6982 (335.25 nm)	0.0013	0.230103	LE

^aThe numbers in parentheses are the transition energy wavelength.

^bOscillator strength.

^cΔr index is a quantitative indicator of electron excitation mode, which is a measure of CT length.

^dPC₆₁BM and BT in parentheses present the density are localized on the fullerene and polymer, respectively.