Transparent Perovskite-Based Photovoltaic Devices for Selective Ultraviolet Light Harvesting and Visible Light Transmission

Background

The field of transparent photovoltaics has garnered significant interest in recent years due to the growing demand for energy-harvesting solutions that can be seamlessly integrated into everyday surfaces, such as windows and electronic displays. As urban environments become more energy-conscious, the ability to generate electricity from surfaces that traditionally serve only structural or aesthetic purposes presents a compelling opportunity. Transparent solar cells, particularly those that selectively absorb ultraviolet (UV) light while remaining visibly clear, offer the promise of supplementing building energy needs without compromising natural lighting or design. This approach is especially attractive for applications in smart windows, greenhouses, and portable electronics, where both transparency and energy generation are desirable.

Despite the promise of transparent solar technologies, current approaches face several significant challenges. Conventional UV-absorbing solar cells often suffer from low power conversion efficiencies due to poor UV absorption and limited charge carrier mobility in the active layers. Many existing materials either absorb too much visible light, reducing transparency, or fail to efficiently convert UV photons into electrical energy. Additionally, fabrication methods for these devices can result in films with suboptimal thickness, poor crystallinity, or inadequate conductivity, further limiting performance. The trade-off between maximizing transparency and achieving high efficiency has proven difficult to overcome, and integration with tandem cell architectures or electrochromic devices remains technically complex. As a result, there is a pressing need for new material systems and fabrication techniques that can deliver both high UV-selective absorption and excellent visible transparency while maintaining robust photovoltaic performance.

Technology

This technology centers on the development of visibly transparent solar cells that selectively absorb ultraviolet (UV) light using inorganic perovskite films as the active layer. By precisely tuning the halide composition in various perovskite structures—such as three-dimensional ABX₃, double A₂BCX₆, or two-dimensional A₂Bₙ₋₁MₙX₍₃ₙ₊₁₎—the films achieve strong UV absorption (cutoff ≤470 nm) while remaining transparent to visible light. These dense films, typically around 400 nm thick with crystallite sizes greater than 10 nm, are deposited via thermal co-evaporation onto transparent electrodes like ITO or FTO, and can be integrated into both conventional and inverted solar cell architectures. The device stack may include electron transport layers (e.g., TiO₂, SnO₂, ZnO) and hole transport layers (e.g., spiro-OMeTAD, PEDOT:PSS), and is compatible with tandem solar cell configurations or incorporation into electrochromic window assemblies.

What differentiates this technology is its unique combination of high UV conversion efficiency and visible transparency, surpassing the performance of existing UV-absorbing photovoltaics. The ability to finely adjust the perovskite composition allows for optimal absorption in the UV range without sacrificing the clarity required for applications like power-generating windows. The use of inorganic perovskites ensures high conductivity and stability, while the thermal co-evaporation process enables precise control over film thickness and uniformity. Furthermore, the versatility in device architecture and compatibility with tandem and window-integrated designs make this solution adaptable for a wide range of energy-harvesting and building-integrated photovoltaic applications, offering a significant advancement in transparent solar technology.

Benefits

• High ultraviolet light absorption with visible transparency, enabling clear solar cells.
• Improved power conversion efficiency compared to existing UV-absorbing photovoltaics.
• Versatile perovskite compositions (3D, double, 2D) allow tuning of optical and electronic properties.
• Compatibility with conventional and inverted solar cell architectures.
• Thermal co-evaporation deposition enables uniform, dense films with controlled thickness (200–800 nm).
• Integration potential in tandem solar cells and electrochromic window assemblies.
• Use of stable inorganic perovskites enhances device durability and conductivity.

Applications

• Building-integrated transparent solar windows
• Automotive sunroof energy harvesting
• Greenhouse power-generating glass panels
• Transparent photovoltaic device displays
• UV-protective power-generating facades

Additional info

These transparent photovoltaic devices employ inorganic perovskite films as active layers. Tuned halide compositions enable efficient ultraviolet light absorption (cutoff ≤470 nm) while maintaining visible transparency. Dense films, typically 400 nm thick with >10 nm crystallites, are deposited via thermal co-evaporation. These cells offer enhanced UV conversion efficiency and visible transparency, compatible with tandem configurations or electrochromic window integration.