Solution Processed MoO₃ Interfacial Layer for Organic Photovoltaics Prepared by a Facile Synthesis Method

Abstract

An MoO(3) film spin-coated from a solution prepared by an extremely facile and cost-effective synthetic method is introduced as an anode buffer layer of bulk-heterojunction polymer photovoltaic devices. The device efficiency using the MoO(3) anode buffer layer is comparable to that using a conventional PEDOT:PSS layer without annealing at an elevated temperature.

Processing and charge state engineering of MoOx

“…[23][24][25] In view of a reliable device performance, the control over the chemical and physical properties of the MoO x system is mandatory. It has been recently reported 14,[26][27][28][29][30][31][32] that in MoO x with x < 3, oxygen vacancies originated from partially populated d-states, give rise to occupied energy states within the forbidden gap -∼ 3.0 eV at room temperature (RT) 12 -becoming bands above a critical concentration and driving the Fermi level close to the conduction band. The oxygen vacancies concentration, and consequently the averaged oxidation state of Mo, is a key parameter affecting the properties of the MoO x system.…”

Ultrafast laser-assisted synthesis of hydrogenated molybdenum oxides for flexible organic solar cells

“…The XPS O1s spectra of the as-coated MoO 3 shows a peak at 530.6 eV, which is assigned to the Mo-O bond. 17 As the laser energy was increased, an extra peak of hydroxyl groups (-OH) at the binding energy of 532 eV increased gradually. These XPS results indicate that the MoO 3 layer was hydrogenated to form hydrogenated molybdenum oxide (H yMoO 3Àx ).…”

“…[14][15][16] The other method is to use ammonium heptamolybdate as an inexpensive precursor for low-temperature processing (100 C). 17,18 These methods, however, require long processing times to obtain conductivity, leading to restraint from the employment of R2R processes for OSCs. Furthermore, it is hard to implement a micro-pattern on the solution-processed MoO 3 due to several steps in patterning for the implementation of devices.…”

“…However, as a large-area and low-cost roll-to-roll (R2R) fabrication has attracted attention for practical applications, a number of attempts have been conducted to obtain solution-processed MoO 3 as a HTL in OSCs. [10][11][12][13][14][15][16][17][18] Among the various properties of MoO 3 , good electrical conductivity is needed for the HTL. Oxygen vacancies play a key role in obtaining the conductivity of the MoO 3 layer.…”

“…9 Among TMOs, molybdenum oxide (MoO 3 ) is a promising candidate because of its transparency, air stability, and high work function (WF). [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] In the early stages of OSC research, vacuumdeposition was conducted for the fabrication of MoO 3 thin-lms. However, as a large-area and low-cost roll-to-roll (R2R) fabrication has attracted attention for practical applications, a number of attempts have been conducted to obtain solution-processed MoO 3 as a HTL in OSCs.…”