Bifacial Si heterojunction-perovskite organic-inorganic tandem to produce highly efficient (ηT* ∼ 33%) solar cell

Abstract

As single junction thin-film technologies, both Si heterojunction (HIT) and Perovskite based solar cells promise high efficiencies at low cost. One expects that a tandem cell design with these cells connected in series will improve the efficiency further. Using a self-consistent numerical modeling of optical and transport characteristics, however, we find that a traditional series connected tandem design suffers from low due to band-gap mismatch and current matching constraints. It requires careful thickness optimization of Perovskite to achieve any noticeable efficiency gain. Specifically, a traditional tandem cell with state-of-the-art HIT () and Perovskite ( ) sub-cells provides only a modest tandem efficiency of 25%. Instead, we demonstrate that a bifacial HIT/Perovskite tandem design decouples the optoelectronic constraints and provides an innovative path for extraordinary efficiencies. In the bifacial configuration, the same state-of the-art sub-cells achieve a normalized output of =33%, exceeding the bifacial HIT performance at practical albedo reflections. Unlike the traditional design, this bifacial design is relatively insensitive to Perovskite thickness variations, which may translate to simpler manufacture and higher yield.

Thermodynamic efficiency limits of classical and bifacial multi-junction tandem solar cells: An analytical approach

“…The thermodynamics and the optimization of two-junction bifacial cells have been reported recently. 9,10 The results show that the optimization is nontrivial: In a classical MJT, the need for current-matching dictates a sequential decrease in bandgap from the top to the bottom. In a B-MJT, the bottom cell is illuminated by albedo light; therefore, we need not maintain the bandgap sequence; a partial inversion of bandgaps is possible and desirable.…”

“…We first calculate numerically P max ¼ JðV opt ÞV opt , based on Equations (7), (9), and (10), to find g à T ðE 0 ; N; Q ¼ 0; RÞ for N ¼ 1,…, 10 and R ¼ 0, and plot the results in Fig. 2(a).…”

Tandem Solar Cells Based on Cu2O and c-Si Subcells in Parallel Configuration: Numerical Simulation

“…A four-terminal device has the subcells electrically decoupled and independently controllable that can be connected in parallel, ensuring a maximum output power at all times [18]. The tandem efficiency is estimated to reach values above 30% [1,2,6,19]. A possible four-terminal configuration is presented in Figure 1 [20].…”

“…Recently, tandem solar cells made up of various materials such as silicon (monocrystalline, polycrystalline, and amorphous) [1][2][3], perovskite [4][5][6], polymer [7,8], dyesensitized solar cells [9], and quantum dot solar cells [10] have been theoretically or experimentally studied. However, tandems with a high efficiency at low cost have still not been realized.…”

Progress, challenges and perspectives in flexible perovskite solar cells

“…43,44 There has also been interest, as a candidate for a possible initial commercial deployment, in incorporating a top B1 mm thick perovskite subcell in a tandem device with a silicon subcell or a CIGS based thin film device in order to further reduce the cost-efficiency balance of the technology. 45 The tandem configuration should be able to increase the PCE by 20% (bringing it to over 30% in absolute terms) 46 but the best published reports are still well below this target. [46][47][48][49][50][51] Apart from the high PCEs delivered, the key advantage of this new PV technology consists in the possibility of relatively simple processing of the perovskite precursors either via vapour techniques or in solution (i.e.…”