Photon Recycling Strategies in Photovoltaic Technologies

Photon recycling describes the iterative emission and reabsorption of photons within a photovoltaic absorber, converting otherwise lost radiative emissions back into useful charge carriers. By harnessing this process, devices can approach their fundamental thermodynamic limits, raise open-circuit voltage and curb non-radiative losses. Implementing photon recycling requires careful management of optical pathways—through texturing, reflective interfaces, quantum-well barriers or nanophotonic designs—to confine internally generated light and promote its re-entry into the active layer. In perovskite and III–V semiconductors, high internal luminescence yields make photon recycling especially attractive, while in organic and hybrid systems the challenge lies in overcoming interfacial quenching and low radiative efficiencies. Strategies range from suppressing interfacial defects to engineering long-period barrier molecules, embedding photonic crystals or introducing angular light-trapping couplers. Together, these approaches prolong carrier lifetimes, boost charge-carrier density under illumination and narrow the voltage gap imposed by non-ideal recombination. The result is a versatile toolkit for enhancing single-junction power conversion efficiencies, stabilising device operation and paving the way for cost-effective commercial modules, bifacial systems and multijunction tandems that fully capitalise on recycled photons.

Research from Nature Portfolio

Recent studies have demonstrated that embedding tailored barrier layers at perovskite interfaces can simultaneously suppress quenching and facilitate recursive photon pathways. By introducing long-chain organic spacers in a multiple quantum-well configuration, researchers have achieved both high radiative efficiency and certified power conversion in excess of 25 %, while maintaining electroluminescence yields of nearly 20 %. This design stabilises the perovskite lattice against humidity and thermal stress for over 2 years of storage. Seminal work on textured perovskite films has further quantified the direct link between external photoluminescence yield and internal photon cycling, revealing that substrate patterning can more than triple out-coupling efficiency and thereby enhance overall power conversion.

Photon Recycling Strategies in Photovoltaic Technologies publication trend

The graph below shows the total number of articles in photon recycling strategies in photovoltaic technologies across all publications each year (not limited to Nature Index journals).

Technical terms

Photon recycling: The process by which emitted photons are reabsorbed by the active layer, generating additional charge carriers and reducing radiative losses.

Radiative recombination: The decay of an electron–hole pair accompanied by photon emission, contributing to luminescence and enabling recycling.

Non-radiative recombination: Carrier recombination that releases energy as heat rather than light, reducing device voltage and efficiency.

Exciton diffusion: The movement of bound electron–hole pairs (excitons) through a material, which can be enhanced by photon reabsorption events.

References

1. Lattice battery solar cells: Exceeding Shockley–Queisser limit. EcoEnergy (2024).
2. Quantum barriers engineering toward radiative and stable perovskite photovoltaic devices. Nature Communications (2024).
3. Enhancing photoluminescence yields in lead halide perovskites by photon recycling and light out-coupling. Nature Communications (2016).
4. Origins of the long-range exciton diffusion in perovskite nanocrystal films: photon recycling vs exciton hopping. Light: Science & Applications (2021).