Luminescent down-shifting film based on optimized mixture of organic dyes for improving the performance of P3HT:PC61BM photovoltaic devices

Abstract

During the last few years, great interest has been given to research in organic solar cells. Apart from the low cost techniques needed for the production of the active layers, the plasticity of these types of materials offers an additional benefit compared to traditional silicon-based solar cells. However, the commercialization of organic photovoltaic technologies is limited by rapid degradation and low efficiency. Recently, the use of luminescent down-shifting (LDS) films has been explored as a tool for increasing the external quantum efficiency of organic-based devices. A previously observed superposition in the emission–absorption spectra of Kremer blue (Kb) and Coumarin 7 (C7) dyes suggests that an energy transfer process can take place among these molecules. Decay time photoluminescence measurements in Kb100−xC7x samples were carried out to confirm a Föster resonance energy transfer process. An optimization process following the design of experiments methodology was carried out to adjust the optical properties of Kb100−xC7x films for applications in the P3HT:PC61BM organic photovoltaic device. An increment of 18.6% in the short circuit current density (Jsc) of P3HT:PC61BM devices coated with a Kb92.5C77.5 LDS film was observed. A degradation test shows a rapid drop in the electric current density of devices without the LDS film, which we attribute to the so-called burn-in, widely reported in the literature. For devices coated with the Kb92.5C77.5 LDS film, no rapid drop in the electric current density was observed, suggesting that the use of the luminescent layer mitigates the photoinduced burn-in loss.

Down‐conversion materials for organic solar cells: Progress, challenges, and perspectives

“…Later, Perdomo et al applied the KB and C7 dyes by mixing at different ratios for solar cells application. [127] The layer was coated on quartz substrates and put on front side of the device (ITO/PEDOT: PSS/P3HT: PCBM/Al) during J-V measurement. An increment of 18.6% was reported in the J sc , from 0.24 to 0.29 mA/cm 2 with a Kb 92.5 C7 7.5 dye, and it contributed to the PCE improvement from 1.37% to 1.99%.…”

Recent studies of the photovoltaic device enhancement via multifunctional luminescent down-shifting films

“…In recent works, three categories of LDS materials have primarily been utilized for PV modules; quantum dots (QDs), 16,[18][19][20] organic dyes, [21][22][23] and rare-Earth elements. 24,25) Figure 2 exhibits the optical properties of these LDS materials in each category.…”

“…(Color online) Normalized absorbance of matrix materials; PDMS (black), PET (red). 26) Normalized absorbance and photoluminescence of EuD 4 TEA (organic dye) (blue), 22) CdSe QDs (orange), 20) Kb:C7 (rare-Earth element) (purple). 25) Fig.…”

Visually attractive and efficient photovoltaics through luminescent downshifting

“…Certain optical parameters of luminescent molecules, such as broadband absorption (300–500 nm), high molar absorptivity, large Stokes shift, close to unity photo-luminescence quantum efficiency, high photostability, low cost of production and high mass absorptivity (1 g −1 cm −1 ) should be considered when selecting a LDS material for PV cells and their practical implementations. 24–26 To date, various types of luminescent materials including inorganic phosphors, 42 quantum dots, 43 organic dyes 44 and organolanthanide complexes 45 have shown promise as LDS layers in PV cells. Each of these material types has advantages and disadvantages.…”