“Layer‐Filter Threshold” Technique for Near‐Infrared Laser Ablation in Organic Semiconductor Device Processing

Abstract

Although conventional laser ablation (CLA) method has widely been used in patterning of organic semiconductor thin films, its quality control still remains unsatisfied due to the ambiguous photochemical and photothermal processes. Based on industrial available near‐infrared laser source, herein, a novel “layer‐filter threshold” (LFT) technique is proposed, which involves the decomposition of targeted “layer‐filter” and subsequent explosive evaporation process to purge away the upper layers instead of layer‐by‐layer ablation. For photovoltaic device with structure of metal/blend/PEDOT:PSS/ITO/glass, the PEDOT:PSS layer as the “layer‐filter” is first demonstrated to be effective, and then the merged P1–P2 line and metal electrode layer are readily patterned through the “self‐aligned” effect and regulation of ablation direction, respectively. The correlation between laser fluence and explosive ablation efficacy is also investigated. Finally, photovoltaic modules based on classical P3HT:PC61BM and low‐bandgap PBDT‐TFQ:PC71BM systems are separately fabricated following the LFT technique. It is found that over 90% of geometric fill factor is achieved while device performances maintain in a limited change with increased number of series cells. In comparison to conventional laser ablation methods, the LFT technique does not require sophisticated instruments but reaches comparable processing accuracy, which shows promising potential in the fabrication and commercialization of organic semiconductor thin‐film devices.

Solution-Processed Organic Thin-Film Transistor Arrays with the Assistance of Laser Ablation

“…In order to obtain the high-performance OTFT array, the thermal effect must be reduced as much as possible. It should be pointed out that a laser at the visible region was previously reported for organic layer ablation, as the absorption at the near-infrared of organic polymers is intrinsically weak. − Thus, most of the laser absorption and energy transfer was confined within the Ag layer under the irradiation of the laser with 1064 nm wavelength. Meanwhile, the thermal conductivity of organic semiconductors was relatively low to the metal thermal conductivity.…”

Laser Processing in the Manufacture of Dye‐Sensitized and Perovskite Solar Cell Technologies

“…The same can be said about procedures developed in the organic photovoltaics (OPVs) field. Many recent developments to optimize laser processing of PV modules based on organic semiconductors have been reported in the literature, which should enable the high‐throughput manufacture of these thin‐film modules, whilst ensuring high geometrical aperture ratios . Inactive or dead areas as low as 200 μm have been reported, with module geometrical aperture ratios larger than 90–97%.…”

Direct laser patterning of organic semiconductors for high performance OFET-based gas sensors

“…Femtosecond laser (fs) processing is a universal mask-free technology which can be used to fabricate fine micro/nanostructures with extremely high resolution in numerous material systems, providing impressive advances in materials science, industrial and medical fields. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Recently, Guo et al showed a facilely fs laser patterning of polymer OSC thin films by taking advantage of the ablation effect of fs laser irradiation. 34 Furthermore, this novel fs-laser patterning strategy was demonstrated to be able to create an organic field-effect transistor (OFET) array with a high device density of 6250 cm À2 on soft substrates and the resulting OFET array showed promising potential in image sensor applications.…”