From binary to multicomponent photoactive layer: A promising complementary strategy to efficient hybrid solar cells

A strategy is demonstrated for fabrication of highly efficient hybrid solar cells based on the polymer/nanoarrays with complementary multicomponents in photoactive layer, including a scenario to controllably synthesize ternary ZnO/CdS/Sb₂S₃-core/shell/shell nanoarrays (ZCS-NAs) for a high open-circuit voltage (V_oc) and short-circuit current and an approach to dope amorphous polymer with lithium bis(trifluoromethanesulfonyl) amide at nanoscale for a remarkably improved fill factor. With the integrated benefits from the complementary multicomponents having optimized nanoarray structure and doping concentration, an efficiency up to 5.01% under AM 1.5 illumination (100mW/cm²) is achieved in the polymer/ZCS-NA devices with poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) as the polymer. To the best of our knowledge, this is the highest efficiency in the polymer/nanoarray devices. It is found that the V_oc in the multicomponent solar cells is determined by the band level difference between ZnO core and polymer, and sufficient photo-excitation of the polymer is necessary for efficient photocurrent generation. The component effects on device performance are elucidated and a model concerning the effective polymer phase and illumination attenuation between nanorods is proposed for understanding the charge generation from polymer absorption in the multicomponent solar cells.