Experimental evidence of hot carriers solar cell operation in multi-quantum wells heterostructures

Abstract

International audienceWe investigated a semiconductor heterostructure based on InGaAsP multi quantum wells (QWs) using optical characterizations and demonstrate its potential to work as a hot carrier cell absorber. By analyzing photoluminescence spectra, the quasi Fermi level splitting Dl and the carrier temperature are quantitatively measured as a function of the excitation power. Moreover, both thermodynamics values are measured at the QWs and the barrier emission energy. High values of Dl are found for both transition, and high carrier temperature values in the QWs. Remarkably, the quasi Fermi level splitting measured at the barrier energy exceeds the absorption threshold of the QWs. This indicates a working condition beyond the classical Shockley-Queisser limit

Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling

“…2(a). The PL can be modeled via a generalized Planck radiation law 30,31 :where, is the emitted photon energy, A is the absorptivity, Δ μ is the chemical potential or quasi-Fermi-level separation under laser excitation, and T C represents the non-equilibrium hot carrier temperature. In the simplest case, taking a linear fit to the high-energy tail of the natural logarithm of a PL spectrum determines the carrier temperature 14,15,24,25,32 .…”

Optoelectronic characterization of carrier extraction in a hot carrier photovoltaic cell structure

“…The dependence on light intensity was explored as this is a key factor to control for when determining the hot carrier IV response of a cell to different wavelengths of light. Previously other authors [11]- [14] have shown strong hot carrier effects based on heating electron populations through increased light intensity, observing carrier temperature dependent features in the PL emission of their structures. However, this method of generating hot carriers (generating different temperatures with different illumination intensities) causes difficulty in analysis and interpretation when we examine the current from the structure rather than solely its optical emission.…”

Entropy production in photovoltaic-thermoelectric nanodevices from the non-equilibrium Green’s function formalism

“…From a fundamental point of view, this direction is related to the thermodynamics of light [21] which has naturally emerged in photovoltaics regarding the photon source as a thermal bath [22], and the thermoelectricity at contact between absorber and lead [23,24]. Closer to the commercial level, the creation and performance analysis of stacked photovoltaic-thermoelectric modules have been reported [25,26].…”