Speaker
Description
The idea of using quantum dots (QD) to extend the spectral sensitivity and improve the efficiency of solar cells was first put forward by Aroutiounian et al. (J. Appl. Phys. 89, 2268, 2001). QDs indeed provide several useful knobs in photovoltaics, such as tuning the bandgap for a certain spectrum and concentration, realizing current-matched multiple junction cells, and improving radiation hardness in space. On the other hand, the expectation of overcoming the Shockley-Queisser limit of single-gap cells with QD solar cells is yet unfulfilled. For this to happen, it is necessary to engineer the nanostructures to suppress phonon assisted coupling between extended and quantum-confined states, and within intraband confined states too. In this way, one could realize by means of QDs the intermediate band (IB) solar cell (Luque et al., Phys. Rev. Lett., 78, 26, 1997), which has a theoretical efficiency about 50% higher than its single-gap counterpart under unconcentrated light. Three decades of extensive research, mostly on self-assembled III-V QDs, has led to observe the fundamental mechanisms of the IB solar cell at cryogenic temperatures but the demonstration of a high efficiency IB cell is yet to come. Recently, new materials have emerged, such as strain-free III-V QDs and colloidal QDs into perovskite absorbers, with promising features for IB operation at room temperature. In this talk, I will revisit the physics and limits of QD solar cells, considering optical and transport simulations and discuss possible ways forward for their development, both in the perspective of single-gap and IB operation.
| Type of presence | Presence online |
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