• Universitat de València

• Juan Ferrera González

Photovoltaics stands as the leading renewable energy technology, although it presents limited spectral utilization. Solar cells predominantly harness the visible spectrum, leaving untapped potential in the infrared and ultraviolet ranges. The remedy to this constraint lies in upconversion technology, capable of harvesting lower-energy photons and transforming them into visible light. Upconversion nanoparticles have become a pivotal component, particularly lanthanide-upconversion nanoparticles, capable of efficient upconversion emission. Recent research has also witnessed the integration of upconversion nanoparticles with lead halide perovskites. These perovskites are known for their exceptional light-harvesting abilities, thanks to their broad absorption spectrum, high absorption coefficients, and superior photoconversion efficiency. However, previous attempts to merge upconversion nanoparticles with perovskites resulted in suboptimal sensitized emission efficiency due to energy transfer limitations. This issue highlighted the need for materials that could enhance both energy conversion efficiency and stability in photovoltaic devices.

Researchers from the Universitat de València have developed a novel hybrid material that combines inorganic halide perovskite nanoparticles (LHPNPs) and upconversion nanoparticles (UCNPs) within tube-shaped lead salt nanoclusters. This hybrid material exhibits remarkable absorption and emission properties, resulting in bright green emission under UV light and significantly improved energy transfer efficiency from upconversion nanoparticles to perovskite nanoparticles. Additionally, this hybrid material enables the creation of films with remarkable sensitized emission efficiency, excellent morphology, and stability following international standards (ISOS) for organic photovoltaic stability.

The invention also covers methods for preparing the hybrid material and the use of this material in the photovoltaic industry. The rational arrangement of nanoparticles within nanoclusters enhances sensitized emission efficiency through the Forster Resonance Energy Transfer (FRET) mechanism, leading to minimal energy loss. Films created from this hybrid material are uniformly structured without cracks or voids and exhibit enhanced quantum yield and sensitized emission efficiency. This confirms the occurrence of resonance energy transfer (RET) between upconversion and perovskite nanoparticles, resulting in films with exceptional optical stability.

The invention is applicable in photovoltaics devices.

The invention has the following advantages:

• Superior absorption and emission properties
• Improved optical characteristics, resulting in a vibrant green emission when exposed to UV light and increased efficiency in the transfer of energy from UCNPs to LHPNPs.
• Remarkable sensitized emission efficiency, coupled with outstanding morphology and stability in hybrid films, as per ISOS protocols, attributable to the hybrid material.
• Well-suited for use in photovoltaic devices due to its higher efficiency yield and enhanced stability.
• Elevated quantum yield and enhanced sensitized emission efficiency of the perovskite nanoparticles.
• Significant optical stability.

• Patent granted