Highly Efficient Semitransparent Organic Solar Cells with Color Rendering Index Approaching 100.

Neutral-colored semitransparent organic solar cells (ST-OSCs) have attracted considerable attention owing to their unique application in no-visual-obstacle building-integrated photovoltaics. Toward this promising potential application, a synergistic effect is first proposed by employing a dielectric mirror and ternary photoactive layer with near-infrared absorption to tune the color perception as well as ST-OSC performance precisely. As a result, a neutral-color ST-OSC with high average transmittance of over 21% is successfully constructed, and a remarkable color-rendering index approaching 100 and high power conversion efficiency (PCE) of 9.37% are simultaneously achieved. To the best of our knowledge, this is the highest PCE reported for neutral-color ST-OSCs to date. Importantly, this synergistic effect is demonstrated to be a universal strategy that is not only suitable for various photoactive layer systems, but can also be implanted in flexible substrate. The resulting neutral-color flexible ST-OSCs also show a promising PCE of 8.76%.