Exploring dynamics of resonance energy transfer in hybrid Quantum Dot Sensitized Solar Cells (QDSSC)

Abstract

Graphene based nanomaterials are known to provide new avenues to improve semiconductor based light harvesting devices. This work makes use of graphene quantum dots (GQD) to improve the efficiency of a CdSe Quantum Dot Sensitized Solar Cell (QDSSC) by Förster Resonance Energy Transfer (FRET) mechanism. FRET describes non-radiative energy transfer between two adjacent molecules typically in range from 1 to 10 nm with one molecule as donor and other molecule as acceptor. If the acceptor is in close proximity of the excited donor, then their dipoles align resulting in transfer of excitation energy from donor to acceptor. Here graphene quantum dot acts as the energy donor to enhance light harvesting of CdSe quantum dot which acts as an acceptor in the hybrid solar cell. The introduction of GQD increases the efficiency of CdSe sensitized QDSSC from 0.18 to 0.28% showing an efficiency enhancement of 55%. The improved efficiency is mainly attributed to the 46% increase in current density of the GQD-CdSe solar cell compared to the CdSe QDSSC. The increased performance of the QDSSC owes to the existence of non-radiative energy transfer (FRET) between GQD and CdSe evident from photoluminescence (PL) quenching and lifetime measurements. This FRET system of GQD (donor)-CdSe (acceptor) shows an energy transfer of 48.7% providing new insights for selective light harvesting of the solar spectrum which can be utilised for various potential applications in future.

Photothermal therapy using graphene quantum dots

“…Copyright 2020 Author(s). 88 (i) UV-VIS spectroscopy. Reprinted with permission from Naik et al, J. Nanostruct.…”

Cadmium Selenide Quantum Dots for Solar Cell Applications: A Review

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Shedding Light on Graphene Quantum Dots: Key Synthetic Strategies, Characterization Tools, and Cutting-Edge Applications

“…In this case, GQDs mainly acted as a charge recombination suppressor, as electron impedance spectroscopy and transient photovoltage decay measurements confirmed; after optimizing the GQD coating deposition in terms of deposition sequence, concentration, and time, the final devices offered an improved PCE of 6.59% under AM 1.5G full one sun illumination. Recently, PL quenching and lifetime measurements revealed that, in the case of GQDs/CdSe quantum dots, it is also possible to identify the FRET mechanism, so as to gain deeper knowledge of the system, aiming at further performance improvements [ 185 ]. Similar results were recently reported by Kolay and collaborators for a different design centered around CdS quantum dots as the main photosensitizer [ 186 ]; the performance was similar in terms of PCE, although the design was more complex in terms of the fabrication protocol.…”