Solar cell technology requires materials that are efficient, lightweight, and stable. Organic–inorganic lead halide perovskite- and polymer-based bulk heterojunction solar cells have emerged as highly promising, ultralightweight, flexible, and highly efficient power sources. However, they suffer from limited stability, which is significantly affected by the cell temperature, in addition to other factors like oxidization and moisture in the absence of appropriate encapsulation. Here, by performing a coupled opto-electro-thermal modeling, we report the design of a compatible and novel, ultrathin, submicron, multipurpose organic–inorganic hybrid radiative cooling coating/scheme that, by providing photonic cooling, decreases the cell temperature by up to ∼7.2 K compared to the encapsulated ultrathin solar cell technology, without requiring any external energy input. In addition to the significant temperature reduction, the power conversion efficiency of cells also increases, fulfilling the requirements of high performance at minimal weight, combined with high stability and flexibility, paving the way for next-generation, stable and efficient, ultralightweight solar cells.