A hot-carrier solar cell with optical energy selective contacts

Abstract

The hot-carrier solar cell (HC-SC) is an ambitious approach to solar energy conversion which in principle can achieve high efficiency (84%) from a single bandgap semiconductor. Here we propose a method of utilising hot-carriers within a photovoltaic device in which energy is extracted optically from a hot-carrier distribution rather than through the usual approach of electrical conduction. Depending on the optical extraction rate, the concept proposed here may attain an upper efficiency approaching that of the conventional HC-SC.

Step-like increase of quantum yield of 1.5 μm Er-related emission in SiO2 doped with Si nanocrystals

“…Different strategies of hotcarrier solar cells have been considered and theoretically modelled in the past. [43][44][45][46][47][48][49][50][51] Based on the results of the present study, we propose the use of a thin layer of an optimized SiO 2 doped with Si NCs and Er 3þ ions to absorb the high energy photons, whose conversion efficiency in a standard Si cell is the lowest, and transform them into a stream of 0.8 eV photons, while the lower energy photons would pass through that layer to undergo photovoltaic conversion in a conventional cell. On the other hand, the 0.8 eV photons generated in the top layer would not be absorbed by the Si cell and could be directed to a dedicated low energy bandgap cell, e.g., positioned underneath.…”

Requisites for Highly Efficient Hot-Carrier Solar Cells

“…Another new concept to solve the issues on the ESCs is optical extraction of hot-carrier energies proposed by Farrell et al [96]. In general, radiative recombination lifetime τ rad ranges from several hundred picoseconds to several nanoseconds, which is significantly longer than τ th (see Fig.…”

Thermodynamic Efficiency Limits for Optically Boosted Planar Solar Cells

“…Such radiation spectrally matches the band-gap energy of a single-junction cell, thus ideally reducing both losses (i.e., sub-band-gap and aboveband-gap losses) to zero. This approach was represented by closely related concepts, either the thermophotovoltaic converter [9][10][11] with filter [12] or the optical analog of HCSC [13]. Unlike up-and down-conversion, an optical bandpass filter (e.g., distributed Bragg reflector) is required to narrow down the energy exchange between the converter and the underlying photovoltaic cell within a nearmonochromatic spectral region.…”

“…The previous work on the optically coupled photovoltaic system [6,7,12,13] always assumes photon fluxes in both thermal and chemical FIG. 1.…”

“…Two geometrical configurations are presented in Fig. 1 [13] which place the lossless converter at the front and at the back of the cell, respectively. Following the assumption adopted in the well-known SQ model [1], the singlejunction solar cell is regarded as a blackbody (for energies above the band gap w 0 ).…”