ICFO scientists cut Boltzmann loss in solar cells, opening path to 43% efficiency

Researchers at ICFO in Barcelona have experimentally demonstrated a way to reduce Boltzmann loss in solar cells by narrowing the angular range of photon emission. The work, published in Energy & Environmental Science, uses an inverted organic PM6:Y6 cell turned into an optical cavity and could offer a route beyond the 33.16% Shockley–Queisser limit, theoretically approaching 43%.

• Boltzmann loss stems from the mismatch between the narrow absorption cone and broad emission cone
• An optical cavity with silver electrodes suppresses photon emission at large angles
• The Shockley–Queisser limit for single-junction cells is 33.16%; the theoretical ceiling is about 43%
• The approach adds no extra fabrication complexity and could apply to other photovoltaic technologies