Nanograting Structured Ultrathin Substrate for Ultraflexible Organic Photovoltaics

Abstract

The nanopatterning of the surfaces of polymer substrates enhances the performances of photovoltaics. Ultraflexible organic photovoltaics (OPVs) are one of the promising energy harvesters for wearable electronics. A reduction in incident light angle dependence while maintaining the power conversion efficiency (PCE) is desirable for wearable electronics devices in which the angle of incident light continuously changes due to the deformation of the device. However, the nanopatterning of the ultrathin polymer substrates of ultraflexible OPVs using the reported methods is challenging because they fatally damage the substrates. Here, the fabrication of ultraflexible OPVs having a low incident light angle dependence while maintaining a PCE of 10.5% by developing ultrathin nanograting polymer substrates is reported. The nanograting‐patterned fluorinated polymer enables the formation of periodic nanograting structures onto the back surface of a 1 µm thick polymer substrate having a pitch of 760 nm and a height of 100 nm, while the opposite surface remains flat after the formation of the planarization layer. Furthermore, with the nanopatterning of the ultrathin substrate, electron‐transporting layer, and active layer, the ultraflexible OPVs exhibit a PCE of 10.8%. The combination of new materials with the developed patterning method is expected to afford even greater performances.

Crumple Durable Ultraflexible Organic Solar Cells with an Excellent Power‐per‐Weight Performance

“…[29][30][31] Although the attractive features of ultraflexible OSCs have been demonstrated, achieving simultaneously high efficiency and excellent mechanical durability is still challenging, especially under large strain (random wrinkling or stretching). [32][33][34] When compared with fullerene receptors, non-fullerene receptors (e.g., 3,9-bis (2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]s-indaceno [1,2-b:5,6-b′]dithiophene series reported by Zhan's group [35] and Y6-series reported by Zou's group [36] ) usually need to be finely optimized their morphologies to form highly crystalline phases with enhanced intermolecular π-π stacking to overcome the relatively low electron mobilities. [37][38][39][40][41] Unfortunately, although increasing crystallinity is beneficial to carrier transport, it also leads to poor phase separation and thereby…”

Multifunctional Structured Platforms: From Patterning of Polymer-Based Films to Their Subsequent Filling with Various Nanomaterials

“…There is a variety of structures that can be obtained with TNIL ( Table 2 ) and employed in different biological applications [ 111 , 113 , 114 , 119 , 120 ], organic photovoltaics [ 121 ], interfaces [ 122 ], superhydrophobic surfaces [ 107 ], memory elements [ 123 ], dental implants [ 124 ], etc. Miniaturized patterns obtained by TNIL and consisting in poly(benzyl methacrylate) (PBMA) lines/2D gratings and nanoholes were recently reported [ 87 ] ( Figure 6 a–b).…”

“…The width of lines was measured to be 10 nm, while diameters of nanoholes were around 20 nm, respectively. Patterns that can be obtained using TNIL include lines of proteins [ 125 ], Nafion [ 126 ], poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) [ 122 ], PMMA [ 123 ], poly(vinyl pyrrolidone) (PVP) [ 123 ], poly(vinyl acetate) (PVAc) [ 123 ], P3HT [ 104 ], or fluorinated polymer gratings [ 121 ] or azopolimeric [ 113 ] and gelatin [ 124 ] pillars, or poly( d,l -lactide-co-caprolactone) (PLCL) [ 111 ] and polyacrylamide (PAM) [ 119 ] grooves, or gelatin holes [ 124 ], etc.…”

Ultra-Flexible Organic Solar Cell Based on Indium-Zinc-Tin Oxide Transparent Electrode for Power Source of Wearable Devices

“…Therefore, when applied to biosensors, improving the accuracy of the collection and analysis of biosignals is possible [1]. In addition, due to the thickness of UFOPVs not exceeding 5 µm, they have excellent adaptability to skin and other tissues given their flexibility and adhesion to 3D surfaces [12]. Therefore, in order to apply UFOPVs as power sources for wearable devices, such as implantable or attachable biosensors, the following conditions must be satisfied.…”

“…Although the results of using IZTO for various purposes has been explored by other researchers, no study evaluating its mechanical properties using transparent electrodes for UFOPVs [28][29][30] had been done. Parylene has excellent optical transmittance (>90%), thermal stability (>290 • C), and chemical stability, making it suitable as an ultra-flexible substrate material [1,12,31]. The IZTO transparent electrode was fabricated using a sputtering target composed of 70 at.% In 2 O 3 -15 at.% ZnO-15 at.% SnO 2 and deposited by pulsed DC magnetron sputtering system.…”