Toward Rollable Printed Perovskite Solar Cells for Deployment in Low-Earth Orbit Space Applications

The thin physical profile of perovskite-based solar cells (PSCs) fabricated on flexible substrates provides the prospect of a disruptive increase in specific power (power-to-mass ratio), an important figure-of-merit for solar cells to be used in space applications. In contrast to recent reports on space applications of PSCs which focus on rigid glass-based devices, in this work we investigate the suitability of flexible PSCs for low-earth orbit (LEO) applications, where the perovskite layer in the PSCs was prepared using either a Ruddlesden–Popper precursor composition (BA2MA3Pb4I13; BA = butylammonium, MA = methylammonium) or a mixed-cation precursor composition (Cs0.05FA0.81MA0.14Pb2.55Br0.45; FA = formamidinium). The flexible PSC devices display a tolerance to high-energy proton (14 MeV) and electron (>1 MeV) radiation comparable with, or superior to, equivalent glass-based PSC devices. The photovoltaic performance of the PSCs is found to be significantly less dependent on angle-of-incidence than GaAs-based triple-junction solar cells commonly used for space applications. Results from a preliminary test of the robustness of the perovskite film when subjected to LEO-like thermal environments are also reported. In addition, a unique deployment concept integrating printed flexible solar cells with titanium–nickel based shape memory alloy ribbons is presented for thermally actuated deployment of flexible solar cells from a rolled state

Toward Rollable Printed Perovskite Solar Cells for Deployment in Low-Earth Orbit Space Applications

The thin physical profile of perovskite-based solar cells (PSCs) fabricated on flexible substrates provides the prospect of a disruptive increase in specific power (power-to-mass ratio), an important figure-of-merit for solar cells to be used in space applications. In contrast to recent reports on space applications of PSCs which focus on rigid glass-based devices, in this work we investigate the suitability of flexible PSCs for low-earth orbit (LEO) applications, where the perovskite layer in the PSCs was prepared using either a Ruddlesden–Popper precursor composition (BA2MA3Pb4I13; BA = butylammonium, MA = methylammonium) or a mixed-cation precursor composition (Cs0.05FA0.81MA0.14Pb2.55Br0.45; FA = formamidinium). The flexible PSC devices display a tolerance to high-energy proton (14 MeV) and electron (>1 MeV) radiation comparable with, or superior to, equivalent glass-based PSC devices. The photovoltaic performance of the PSCs is found to be significantly less dependent on angle-of-incidence than GaAs-based triple-junction solar cells commonly used for space applications. Results from a preliminary test of the robustness of the perovskite film when subjected to LEO-like thermal environments are also reported. In addition, a unique deployment concept integrating printed flexible solar cells with titanium–nickel based shape memory alloy ribbons is presented for thermally actuated deployment of flexible solar cells from a rolled state

Aggregation of a Dibenzo[<i>b</i>,<i>def</i>]chrysene Based Organic Photovoltaic Material in Solution

Detailed electrochemical studies have been undertaken on molecular aggregation of the organic semiconductor 7,14-bis­((triisopropylsilyl)-ethynyl)­dibenzo­[<i>b</i>,<i>def</i>]­chrysene (TIPS-DBC), which is used as an electron donor material in organic solar cells. Intermolecular association of neutral TIPS-DBC molecules was established by using ¹H NMR spectroscopy as well as by the pronounced dependence of the color of TIPS-DBC solutions on concentration. Diffusion limited current data provided by near steady-state voltammetry also reveal aggregation. Furthermore, variation of concentration produces large changes in shapes of transient DC and Fourier transformed AC (FTAC) voltammograms for oxidation of TIPS-DBC in dichloromethane. Subtle effects of molecular aggregation on the reduction of TIPS-DBC are also revealed by the highly sensitive FTAC voltammetric method. Simulations of FTAC voltammetric data provide estimates of the kinetic and thermodynamic parameters associated with oxidation and reduction of TIPS-DBC. Significantly, aggregation of TIPS-DBC facilitates both one-electron oxidation and reduction by shifting the reversible potentials to less and more positive values, respectively. EPR spectroscopy is used to establish the identity of one-electron oxidized and reduced forms of TIPS-DBC. Implications of molecular aggregation on the HOMO energy level in solution are considered with respect to efficiency of organic photovoltaic devices utilizing TIPS-DBC as an electron donor material