Balancing Aesthetics and Performance: An RGB-Based Coloring Strategy for Building-Integrated Photovoltaics.

Building-integrated photovoltaics (BIPV) represents a promising approach for energy generation in urban environments, although balancing aesthetics and photovoltaic performance remains challenging. This work presents and validates a novel tunable coloring strategy for flexible Cu(In,Ga)Se2 (CIGS) solar cells that allows to balance optical induced losses with gains while reducing color angle dependence. Inspired by the light-emitting diode display technology, the strategy combines micropatterned Red, Green, and Blue Bragg reflector (BR) coatings in adjustable proportions to achieve tailored colors. Two line-based microarchitectures were fabricated on soda lime glass and flexible CIGS solar cells. White coloration was selected due to its compatibility with common building facades, with patterns designed to appear visually uniform at distances higher than a 1 m viewing distance. The developed process demonstrated reproducible defect-free microfabrication and successful color perception. Compared to conventional uniform BRs, the RGB pixel coloration strategy significantly reduced color angle dependence and improved optical performance, limiting short-circuit current density losses to below 1.5 mA·cm-2. Moreover, individual color BR led to a short-circuit current loss of 1% to 4% or an enhancement of nearly 10% depending on the final color. The proposed strategy demonstrates strong potential for efficient, aesthetically integrated colored BIPV applications.