Energy Tracing of Photovoltaic Cells

Abstract

Where did the solar energy go in photovoltaic cells in addition to the electricity? Herein, a detailed analytical derivation and numerical investigation on tracing the energy in solar cells (SCs) driven by various mechanisms are presented. Particularly, the critical factors constraining the SC performance are addressed, i.e., the energy and voltage losses. Six categories of intrinsic losses and three categories of potential losses in SCs are identified, in which the sum of Joule and Peltier losses show a constant under a specific bias and can be regarded as a self‐heating effect within SC; moreover, it is strongly dependent with the key material/device parameters, which can be effectively decreased for a realistic (with carrier recombination) SC system so that approaches the limiting efficiency. To bridge the energy loss and the temperature characteristics, an opto–electro–thermal model is developed to accurately mimic the multiphysics responses of SCs. For Si/perovskite and perovskite/perovskite double‐junction SCs, the energy‐tracing study explains the various energy factors limiting the highest efficiency and predicts an efficiency up to 37.5% by an optimal Si/perovskite double‐junction design. The energy‐based study promotes the understanding of the fundamental photovoltaic physics for the possibilities of new photoconversion strategies with higher performances.

Optimizing Crystallization in Wide‐Bandgap Mixed Halide Perovskites for High‐Efficiency Solar Cells

“…According to the detailed balance theory, the maximum efficiency (and V OC ) of perovskite photovoltaics with these bandgaps are 28.6% (1.44 V), 27.5% (1.49 V), 26.2% (1.55 V), and 24.9% (1.6 V). [13] Our devices attained 90% of the Shockley-Queisser (SQ) limit for the fill factor (FF) among all WBG PSCs. The V OC reached 91% and 87% of the SQ limit for V OC (V OC SQ ) when the bandgaps were 1.73 and 1.92 eV, respectively.…”

Thermodynamic Processes of Perovskite Photovoltaic Devices: Mechanisms, Simulation, and Manipulation

“…Moreover, the corresponding J-V and temperature curves as well as energy distributions of single-and double-junction tandem PSCs at MPP conditions are illustrated Figure 6c,d, respectively. We can conclude from these results that: 1) due to the more reasonable use of absorbed light, the thermalization loss is significantly reduced from 217.8 W m −2 (single-junction) to 145.4 W m −2 (tandem), confirming the feasibility of tandem design to reduce the thermalization loss; [16] 2) the tandem PSC produces a high energy output of 294.9 W m −2 , which is much higher than 223.2 W m −2 inherent to the single-junction system; 3) the contributions of Joule, Peltier and recombination heats of the tandem devices are slightly increased compared with the singlejunction devices, which can be attributed to the fact that the tandem devices produce higher optical absorption than that of the single-junction devices; 4) thanks to the lower heat generation and higher energy utilization, the double-junction tandem devices receive a lower predicted temperature of 37.9 °C at MPP, much lower than that of the single-junction devices (51.8 °C).…”

“…To address this issue, a large number of theoretical studies have been made. [16] For instance, Hirst et al proposed an analytical approach to identify and quantify intrinsic losses of a single threshold cell. [17] Our group developed a rigorous optoelectro-thermal (OET) model for better understanding of carrier thermodynamic behavior of an SC.…”

Reduced 0.418 V VOC-deficit of 1.73 eV wide-bandgap perovskite solar cells assisted by dual chlorides for efficient all-perovskite tandems

“…4 Tandem solar cells (TSCs) hold a higher theoretical efficiency than single-junction cells by reducing thermalization losses. 5,6 Perovskites have a wide bandgap tunability from 1.2 to 3.0 eV, which makes them suitable for all-perovskite TSCs. [7][8][9][10] A typical double-junction TSC usually consists of a wide-E g top subcell and a low-E g bottom subcell, which should have matched current densities between the two subcells for a monolithic configuration.…”