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This paper shows that an enhancement in the performance of commercial screen‐printed multi‐crystalline silicon photovoltaic modules can be achieved via luminescent down‐shifting of the incident light. Using fluorescent organic dyes dissolved in the pre‐existing poly‐ethylene vinyl acetate (EVA) encapsulation layer, an increase in the short‐wavelength external quantum efficiency of over 10% absolute, which results in 0.18% absolute higher efficiency, is reported. This approach offers the opportunity for prompt application at production scale, since it neither requires any modification to the module manufacturing process nor does it add to the cost of power generation. Copyright © 2010 John Wiley & Sons, Ltd.

Perovskite solar cells (PSCs) demonstrate excellent power conversion efficiencies (PCEs) but face severe stability challenges. One key degradation mechanism is exposure to ultraviolet (UV) light. However, the impact of different UV bands is not yet well established. Here, we systematically study the stability of PSCs on the basis of a methylammonium lead iodide (CHNHPbI) absorber exposed to (i) 310-317 (UV-B range) and (ii) 360-380 nm (UV-A range), under accelerated conditions. We demonstrate that the investigated UV-B band is detrimental to the stability of PSCs, resulting in PCE degradation by more than 50% after an exposure period >1700 sun-hours. This finding is valid for architectures with a range of electron transport layers, including SnO, compact-TiO, electron-beam TiO, and nanoparticle-TiO. We also show that photodegradation is apparent for high, as well as for low illumination intensities of UV-B light, but not for illumination with UV-A wavelengths. Finally, we show that degradation of PSCs is preventable at the cost of a small fraction of photocurrent by using UV-filtering or luminescent downshifting layers.

One of the most important elements of a luminescent solar concentrator (LSC) is the host material. In this work, we investigate the key optical properties of eight polymeric host matrices. Poly(methyl methacrylate) (PMMA) and polycarbonate (PC) based formulations exhibited the lowest internal absorbance within the spectral range of the absorption and emission bands of a red‐emitting fluorescent organic dye (Lumogen Red 305). The dye absorbance was dependent on the host matrix and was higher for the PC‐based formulations than the other polymers. However, two different doping concentrations were used, and the higher concentration led to the absorption of more than 90 % of the incident photons within the absorption band of the dye in all cases. The overall optical efficiency with respect to edge emission from 60 mm×60 mm×3.2 mm LSCs varied within an absolute value of 1 % for the eight host matrices investigated. The best result achieved in terms of optical efficiency was 8.9 % for PMMA‐ and PC‐based hosts.

Luminescent down shifting (LDS) is a viable way for improving the short‐wavelength response of many photovoltaic technologies, such as cadmium telluride, copper‐indium‐gallium‐(di)selenide and multi‐crystalline silicon solar cells. In this work, we compare the experimental performance of LDS layers fabricated with six organic dyes—both alone and in mixtures—and two polymers with the theoretical predictions obtained by three different approaches: ray‐tracing simulations and two novel theoretical models. The first model is an analytical description of the LDS process and can reproduce the external quantum efficiency of the solar cell with LDS. The second one is based on a collection of figures of merit that address a desired property of the LDS. The three methods show an excellent agreement with the experimental results in the predicted variation of the short‐circuit current (to within 0.5% in most cases) and help to understand the key factors that influence the performance of LDS, such as the optical coupling, surface roughness and scattering or edge losses. This agreement, regardless of the materials used for LDS and the underlying PV technology, not only supports the validity of the models but also suggests this theoretical formalism as a tool for designing optimised LDS layers in the future. Copyright © 2014 John Wiley & Sons, Ltd.