Conventional photovoltaic (PV) cells are fundamentally limited by the Shockley–Queisser (SQ) efficiency limit, largely due to their inability to convert long-wavelength infrared photons into electricity. Unlocking this untapped infrared spectrum remains a key challenge for achieving maximal solar energy conversion efficiency.
While thermoelectric (TE) effects offer a theoretical pathway to convert thermal energy into electrical power, the integration of PV and TE effects within a single PV cell has remained largely unexplored. Key questions persist:Does the TE effect manifest in the PV cells? What are the underlying factors linking PV and TE effects that possibly contribute to enhancing the power conversion efficiency (PCE) of the PV cells?
In a study published in Energy & Environmental Science, a research team led by Prof. Can Li from the Dalian Institute of Chemical Physics (DICP)of the Chinese Academy of Sciences (CAS) has addressed this challenge through synergizing PV and TE effects within a single perovskite solar cells.
Leveraging the low thermal conductivity and intrinsic thermoelectric properties of perovskite materials, the researchers engineered a vertical temperature gradient (ΔT) within the perovskite solar cell. This design simultaneously exploits two mechanisms: short-wavelength photons are converted via the PV effect, while long-wavelength infrared energy—typically lost as heat—is harvested through the TE effect.
By optimizing device architecture and charge transport dynamics, the researchers experimentally demonstrated a synergistic interaction between photogenerated carriers (PV effect) and thermally diffused carriers (TE effect). The integrated approach achieved a PCE of 27.17% at ΔT=10°C in the FAPbI₃-based solar cell— surpassing the baseline PCE of 25.65%. The enhanced PCE is attributed to broader spectral utilization and directional charge carrier transport induced by the engineered temperature gradient, which facilitates more efficient carrier collection.
Our findings demonstrate the synergistic cooperation betweenPV and TE effects in enhancing the performance of PSCs. Looking forward, this strategy holds particular promise for environments with natural temperature gradients—such as marine settings, where cold seawater lies beneath warmer air, or near-space and polar regions, where intense solar irradiation coincides with low ambient temperatures.
"This work experimentally confirms the feasibility of integrating photovoltaic and thermoelectric effects for simultaneous light and heat harvesting, presenting a viable strategy for next-generation high-performance solar technologies." said Prof. LI.