TiOx/Al bilayer as cathode buffer layer for inverted organic solar cell

Abstract

Titanium oxide (TiOx) modified with a thin layer of Al was used as an electron transporting layer in an inverted organic solar cell based on the P3HT/PCBM blend. The thin Al layer was shown to improve the TiOx surface properties, decreased the work-function of TiOx, increased the built-in voltage, and facilitated electron extraction. As a result, good device performance with power conversion efficiency of 3.6%, open circuit voltage of 0.60 V, short circuit current of 9.13 mA/cm2, and fill factor of 0.66 was achieved. The light soaking problem was eliminated compared to the TiOx only device.

Low‐Temperature Solution‐Processed ZnO Electron Transport Layer for Highly Efficient and Stable Planar Perovskite Solar Cells with Efficiency Over 20%

“…This can be further confirmed by the capacitance–voltage ( C–V ) measurements. As shown in Figure a, C – V characteristics of the devices based on ZnO‐TiO x films with different annealing temperatures were taken in the dark at room temperature against different bias voltages with an alternating current (AC) excitation amplitude of 30 mV at a frequency of 5 kHz . For the Schottky diode, according to the Mott–Schottky relation, the junction capacitance shows a bias dependence, C −2 = 2 ( V bi − V )/( A 2 qεε 0 N ), where V bi corresponds to the built‐in potential, V corresponds to the applied voltage, A corresponds to device active surface, q is the elementary charge, ε is the relative dielectric constant of perovskite (assumed to be 6.5 as determined by the diffusion reflection method), ε 0 is the permittivity of vacuum, and N is assumed to be the doping density of perovskite.…”

Reducing Burn‐In Loss of Organic Photovoltaics by a Robust Electron‐Transporting Layer

“…However, photons with high energy and/or precursors with high kinetic energy can damage the photoactive layer during the deposition and result in the reduction of device performance. [20,32] However, a high condensation temperature (120-150 °C) is generally required to form the amorphous TiO x network from the hydrolyzed TiO x film. [29,30] An amorphous transition metal oxide network can be obtained via hydrolysis and condensation of transition metal alkoxide.…”

“…Thus, significant efforts have been made to develop various electron-transporting layer (ETL) materials for OPVs such as transition metal oxides, [13] carbon-based materials, [14] polymers, [15] low work function metal salts, [16] and organicinorganic hybrids. Various types of transition metal oxides such as zinc oxide (ZnO), [19] titanium oxide (TiO 2 or TiO x ), [20][21][22] tin oxide (SnO 2 or SnO x ), [23] and niobium oxide (Nb 2 O 5 or NbO x ) [24] have been explored for use as ETL materials for OPVs. [5,18] Additionally, transition metal oxide ETLs provide an excellent barrier property against oxygen and metal electrode diffusion compared to organic ETL materials.…”

“…[17] Among various ETL materials, transition metal oxides are commonly utilized because of their adequate highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, stability, transparency, and excellent electron mobility. Various types of transition metal oxides such as zinc oxide (ZnO), [19] titanium oxide (TiO 2 or TiO x ), [20][21][22] tin oxide (SnO 2 or SnO x ), [23] and niobium oxide (Nb 2 O 5 or NbO x ) [24] have been explored for use as ETL materials for OPVs. Various types of transition metal oxides such as zinc oxide (ZnO), [19] titanium oxide (TiO 2 or TiO x ), [20][21][22] tin oxide (SnO 2 or SnO x ), [23] and niobium oxide (Nb 2 O 5 or NbO x ) [24] have been explored for use as ETL materials for OPVs.…”

Orderly Nanopatterned Indium Tin Oxide Electrode Combined with Atomic‐Layer‐Deposited Metal Oxide Interlayer for Inverted Organic Solar Cells

“…[1][2][3][4][5][6][7][8][9] Even though the power conversion efficiency (PCE) for bulk heterojunction (BHJ) solar cells has reached more than 9%, [10][11][12] further improvements to PCE are still the main focus of intensive study.T wo strategies to improve OSC performancea re generally used, namely,t he tuning of the optical and electronic properties of the blend components [13][14][15] and the design of advanced device structures. [16][17][18][19][20][21][22] Thet uning of the optical and electronic properties of the blend components can increaset he opencircuit voltage (V oc )ofthe cell through energy-level engineering [13,14] and the short-circuit currentd ensity (J sc )t hrough bandgap engineering. [15] Thed esign and adoption of advanced device structures can improve the light absorption through light trapping or optical-field arrangement [17][18][19][20][21][22] and decreaset he recombination losses through interface or morphology engineering.…”