Advancements in Colorful Semitransparent Organic Solar Cells: Enhancing Aesthetic Appeal and Efficiency

Aesthetics play a pivotal role in the development of semitransparent organic solar cells (ST‐OSCs), enabling their seamless integration into buildings and various structures without compromising visual appeal while generating electricity. The incorporation of attractive designs not only enhances consumer acceptance and marketability but also broadens the applicability of ST‐OSCs to windows, facades, and electronic devices. Moreover, aesthetically pleasing solar cells foster a positive, ecofriendly image, driving innovation in renewable energy technologies. This study introduces an effective method for advancing the aesthetic appeal of ST‐OSCs through Fabry–Perot microcavity resonance, which increases color saturation by narrowing the transmittance spectrum. A novel Fabry–Perot etalon electrode, consisting of Ag/barium (II) fluoride (BaF 2 )/Ag, is integrated as a top transparent electrode, achieving both high color purity and high‐power conversion efficiency (PCE) in colorful ST‐OSCs. By precisely controlling the thickness of the BaF 2 layer, a wide color gamut with high color purity is achieved, producing vibrant blue, green, and red hues. The photovoltaic devices were fabricated in ambient conditions, with the blue device exhibiting a PCE of 11.52% and a transmittance peak (T%) of 31.66%, the green device showing a PCE of 11.37% with a T% of 26.66%, and the red device achieving a PCE of 11.29% with a T% of 12.24%. These colorful ST‐OSCs, with their required transmitted colors and high color purity, hold significant potential for future developments in energy harvesting.