Low power, non-coherent sensitized photon up-conversion: modelling and perspectives

Abstract

In the last few years, non-coherent sensitized photon up-conversion (SUC) in multi-component systems has been developed to achieve significantly high quantum yields for various chromophore combinations at low excitation powers, spanning from the ultraviolet (UV) to near infrared (NIR) spectrum. This promising photon energy management technique became indeed suitable for wide applications in lighting technology and especially in photovoltaics, being able to recover the sub-bandgap photons lost by current devices. A full and general description of the SUC photophysics will be presented, with the analysis of the parameter affecting the photon conversion quantum yield and the quantities which define the optimal working range of any SUC system, namely the threshold and saturation excitation intensity. It will be shown how these quantities depend on intrinsic photophysical properties of the moieties involved and on the SUC solid host matrix. The model proposed represents a powerful tool for evaluation of a newly proposed system, and its reliability will be discussed in respect to an optimized system with SUC yield of 0.26 ± 0.02. The results obtained will outline the research guidelines which must be pursued to optimize the SUC efficiency for its perspective technological applications.

Effects of Silver and Gold Nanoparticles on Photon Upconversion Based on Sensitized Triplet-Triplet Annihilation

“…The fluorescence spectra of DPA are responsible for PUC-TTA in the solution of PtOEP-DPA system. 15,16) Effect of AgNP on the fluorescence intensity of DPA due to the PUC was examined in Fig. 9.…”

“…The PUC-TTA have been attracting for application of low-intensity incoherent light such as sunlight in photovoltaics and photocatalysts. 15,16) However, the efficiency of the PUC-TTA in condensed media is often quite low. 15,16) The LSPR is expected to improve the efficiency of the PUC-TTA, because the LSPR has been reported to improve the efficiency of optical and optoelectronic devices such as photovoltaic devices as described above.…”

“…15,16) However, the efficiency of the PUC-TTA in condensed media is often quite low. 15,16) The LSPR is expected to improve the efficiency of the PUC-TTA, because the LSPR has been reported to improve the efficiency of optical and optoelectronic devices such as photovoltaic devices as described above. In this study, we examined the effects of AgNP and AuNP on the PUC-TTA using platinum(II) octaethylporphyrin (PtOEP) as a triplet sensitizer (Fig.…”

Efficient Triplet Exciton Fusion in Molecularly Doped Polymer Light‐Emitting Diodes

“…To the best of our knowledge, these values are higher than that of any solid-state TTA-upconverters reported to date [9][10][11][12][13][14]19] and are comparable to some of the best TTA-UC efficiencies observed in solutionphase systems. [9][10][11][12]18] A summary of the efficiencies of solution systems [17,18,[31][32][33] is shown in Table S2 (Supporting Information). Comparisons of our devices with other solid-state TTA-UC systems [13,14,19,31,34] and other TTA-enhanced OLEDs [7,8,[35][36][37] are presented in Tables S3 and S4 (Supporting Information), respectively.…”

“…[9][10][11][12]18] A summary of the efficiencies of solution systems [17,18,[31][32][33] is shown in Table S2 (Supporting Information). Comparisons of our devices with other solid-state TTA-UC systems [13,14,19,31,34] and other TTA-enhanced OLEDs [7,8,[35][36][37] are presented in Tables S3 and S4 (Supporting Information), respectively. The remarkably high TTA-UC efficiencies in our best devices suggest that only singlets are formed during the TTA process.…”