scholarly journals Minimizing Defect States in Lead Halide Perovskite Solar Cell Materials

2020 ◽  
Vol 10 (9) ◽  
pp. 3061 ◽  
Author(s):  
Rosa Brakkee ◽  
René M. Williams
Keyword(s):  
Band Gap ◽  
Chemical Bonding ◽  
Lattice Strain ◽  
Strain Relaxation ◽  
Perovskite Solar Cells ◽  
Vacancy Formation ◽  
Rational Approach ◽  
Computational Studies ◽  
Defect States ◽  
Halide Perovskite

In order to reach the theoretical efficiency limits of lead-based metal halide perovskite solar cells, the voltage should be enhanced because it suffers from non-radiative recombination. Perovskite materials contain intrinsic defects that can act as Shockley–Read–Hall recombination centers. Several experimental and computational studies have characterized such defect states within the band gap. We give a systematic overview of compositional engineering by distinguishing the different defect-reducing mechanisms. Doping effects are divided into influences on: (1) crystallization; (2) lattice properties. Incorporation of dopant influences the lattice properties by: (a) lattice strain relaxation; (b) chemical bonding enhancement; (c) band gap tuning. The intrinsic lattice strain in undoped perovskite was shown to induce vacancy formation. The incorporation of smaller ions, such as Cl, F and Cd, increases the energy for vacancy formation. Zn doping is reported to induce strain relaxation but also to enhance the chemical bonding. The combination of computational studies using (DFT) calculations quantifying and qualifying the defect-reducing propensities of different dopants with experimental studies is essential for a deeper understanding and unraveling insights, such as the dynamics of iodine vacancies and the photochemistry of the iodine interstitials, and can eventually lead to a more rational approach in the search for optimal photovoltaic materials.

scholarly journals Minimizing Defect States in Lead Halide Perovskite Solar Cell Materials

2020 ◽  
Author(s):  
René M. Williams ◽  
Rosa Brakkee
Keyword(s):  
Band Gap ◽  
Chemical Bonding ◽  
Lattice Strain ◽  
Strain Relaxation ◽  
Vacancy Formation ◽  
Rational Approach ◽  
Computational Studies ◽  
Nonradiative Recombination ◽  
Defect States ◽  
Halide Perovskite

In order to reach the theoretical efficiency limits of lead-based metal halide perovskite solar cells, the voltage should be enhanced because it suffers from nonradiative recombination. Perovskite materials contain intrinsic defects that can act as Shockley-Read-Hall recombination centers. Several experimental and computational studies have characterized such defect states within the band gap. We give a systematic overview of compositional engineering by distinguishing the different defect reducing mechanisms. Doping effects are divided into influences on: (1) Crystallization; (2) Lattice properties. Incorporation of dopant influences the lattice properties by: (a) Lattice strain relaxation; (b) Chemical bonding enhancement; (c) Band gap tuning. The intrinsic lattice strain in undoped perovskite was shown to induce vacancy formation. The incorporation of smaller ions, such as Cl, F and Cd, increases the energy for vacancy formation. Zn doping is reported to induce strain relaxation but also to enhance the chemical bonding. The combination of computational studies using (DFT) calculations quantifying and qualifying the defect reducing propensities of different dopants with experimental studies is essential for deeper understanding and unraveling insights, such as the dynamics of iodine vacancies and the photochemistry of the iodine interstitials, and can eventually lead to a more rational approach in the search for optimal photovoltaic materials.

scholarly journals A Study on the Effect of Ambient Air Plasma Treatment on the Properties of Methylammonium Lead Halide Perovskite Films

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 991 ◽  
Author(s):  
Masoud Shekargoftar ◽  
Jana Jurmanová ◽  
Tomáš Homola
Keyword(s):  
Plasma Treatment ◽  
Band Gap ◽  
Treatment Time ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Surface Barrier ◽  
Air Plasma ◽  
Plasma Treatment Time ◽  
Halide Perovskite ◽  
Air Plasma Treatment

Organic-inorganic halide perovskite materials are considered excellent active layers in the fabrication of highly efficient and low-cost photovoltaic devices. This contribution demonstrates that rapid and low-temperature air-plasma treatment of mixed organic-inorganic halide perovskite film is a promising technique, controlling its opto-electrical surface properties by changing the ratio of organic-to-inorganic components. Plasma treatment of perovskite films was performed with high power-density (25 kW/m2 and 100 W/cm3) diffuse coplanar surface barrier discharge (DCSBD) at 70 °C in ambient air. The results show that short plasma treatment time (1 s, 2 s, and 5 s) led to a relatively enlargement of grain size, however, longer plasma treatment time (10 s and 20 s) led to an etching of the surface. The band-gap energy of the perovskite films was related to the duration of plasma treatment; short periods (≤5 s) led to a widening of the band gap from ~1.66 to 1.73 eV, while longer exposure (>5 s) led to a narrowing of the band gap to approx. 1.63 eV and fast degradation of the film due to etching. Surface analysis demonstrated that the film became homogeneous, with highly oriented crystals, after short plasma treatment; however, prolonging the plasma treatment led to morphological disorders and partial etching of the surface. The plasma treatment approach presented herein addresses important challenges in current perovskite solar cells: tuning the optoelectronic properties and manufacturing homogeneous perovskite films.

Impact of strain relaxation on performance of α-formamidinium lead iodide perovskite solar cells

Science ◽  
2020 ◽  
Vol 370 (6512) ◽  
pp. 108-112 ◽  
Author(s):  
Gwisu Kim ◽  
Hanul Min ◽  
Kyoung Su Lee ◽  
Do Yoon Lee ◽  
So Me Yoon ◽  
...  
Keyword(s):  
Solar Cells ◽  
Lattice Strain ◽  
Urbach Energy ◽  
High Efficiency ◽  
Strain Relaxation ◽  
Perovskite Solar Cells ◽  
Lead Iodide ◽  
Α Phase ◽  
Carrier Trap ◽  
Lead Halide

High-efficiency lead halide perovskite solar cells (PSCs) have been fabricated with α-phase formamidinium lead iodide (FAPbI3) stabilized with multiple cations. The alloyed cations greatly affect the bandgap, carrier dynamics, and stability, as well as lattice strain that creates unwanted carrier trap sites. We substituted cesium (Cs) and methylenediammonium (MDA) cations in FA sites of FAPbI3 and found that 0.03 mol fraction of both MDA and Cs cations lowered lattice strain, which increased carrier lifetime and reduced Urbach energy and defect concentration. The best-performing PSC exhibited power conversion efficiency >25% under 100 milliwatt per square centimeter AM 1.5G illumination (24.4% certified efficiency). Unencapsulated devices maintained >80% of their initial efficiency after 1300 hours in the dark at 85°C.

Distribution of bromine in mixed iodide–bromide organolead perovskites and its impact on photovoltaic performance

2016 ◽  
Vol 4 (41) ◽  
pp. 16191-16197 ◽  
Author(s):  
Yang Zhou ◽  
Feng Wang ◽  
Hong-Hua Fang ◽  
Maria Antonietta Loi ◽  
Fang-Yan Xie ◽  
...  
Keyword(s):  
Solar Cells ◽  
Grain Boundaries ◽  
Photovoltaic Performance ◽  
Perovskite Solar Cells ◽  
Defect States ◽  
Halide Perovskite

The bromine has the role of passivating defect states at grain boundaries and interfaces in mixed halide perovskite solar cells.

Influence of defect states on the performances of planar tin halide perovskite solar cells

2019 ◽  
Vol 40 (3) ◽  
pp. 032201 ◽  
Author(s):  
Shihua Huang ◽  
Zhe Rui ◽  
Dan Chi ◽  
Daxin Bao
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Defect States ◽  
Halide Perovskite

Efficient wide band gap double cation – double halide perovskite solar cells

2017 ◽  
Vol 5 (7) ◽  
pp. 3203-3207 ◽  
Author(s):  
Dávid Forgács ◽  
Daniel Pérez-del-Rey ◽  
Jorge Ávila ◽  
Cristina Momblona ◽  
Lidón Gil-Escrig ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Perovskite Solar Cells ◽  
Wide Band ◽  
Band Gaps ◽  
Wide Band Gap ◽  
Halide Perovskite

We study the properties of the series of compounds Cs0.15FA0.85Pb(BrxI1−x)3, aiming to develop an efficient complementary absorber for MAPbI3 in all-perovskite tandems. A bromide content of 0.7 leads to a band gap of 2 eV and a maximum PCE of 11.5% in solar cells, among the highest reported for band gaps wider than 1.8 eV.

scholarly journals Fully Vacuum-Processed Wide Band Gap Mixed-Halide Perovskite Solar Cells

2017 ◽  
Vol 3 (1) ◽  
pp. 214-219 ◽  
Author(s):  
Giulia Longo ◽  
Cristina Momblona ◽  
Maria-Grazia La-Placa ◽  
Lidón Gil-Escrig ◽  
Michele Sessolo ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Perovskite Solar Cells ◽  
Wide Band ◽  
Wide Band Gap ◽  
Halide Perovskite

scholarly journals Effect of Substitutional Point Defect of Gold (Au) in Indium (In) Site of Double Halide Perovskite (Cs2InSbCl6)

2021 ◽  
pp. 334-339
Author(s):  
I Magaji ◽  
A Shuaibu ◽  
M. S Abubakar ◽  
M Isah
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Solar Cell ◽  
Band Gap ◽  
Density Functional ◽  
Perovskite Solar Cells ◽  
Valence Band Maximum ◽  
Functional Theory ◽  
Solar Cell Application ◽  
Halide Perovskite

Lead (Pb) free (non-toxic) perovskite solar cells materials have attracted great interest in the commercialization of the photovoltaic devices. In this work, density functional theory (DFT) and linear response time-dependent within density functional theory (TDDFT) are used to simulate and investigate the effect of gold (Au) dopedPb-free double halide perovskite A2BB?X6(A = Cs; B = In, Au; B? = Sb; X = Cl) on the structural, electronic, and optical properties for perovskite solar cell application. On the structural properties, bond length and bulk modulus calculations show that the doped compound is more likely to resist deformation than the undoped compound. The calculated band structure for both materials (doped and undoped) reveals the presence of the Valence Band Maximum (VBM) and the Conduction Band Minimum (CBM) at around the same symmetry point which indicates a direct band gap nature (at ???? point). The band gap value for the initial compound (= 0.99 eV) agrees with published theoretical values. For the gold doped compound, the value of the band gap increased to a value of 1.25eV. The result of the optical properties shows that the Au-doped material has higher absorption coefficient, lower reflectivity and higher optical conductivity when compared with the initial, as such demonstrates better properties as a candidate for solar cell applications and in other optoelectronic devices.

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