An Intrinsically Micro‐/Nanostructured Pollen Substrate with Tunable Optical Properties for Optoelectronic Applications

Abstract

There is broad interest in developing photonically active substrates from naturally abundant, minimally processed materials that can help to overcome the environmental challenges of synthetic plastic substrates while also gaining inspiration from biological design principles. To date, most efforts have focused on rationally engineering the micro‐ and nanoscale structural properties of cellulose‐based materials by tuning fibril and fiber dimensions and packing along with chemical modifications, while there is largely untapped potential to design photonically active substrates from other classes of natural materials with distinct morphological features. Herein, the fabrication of a flexible pollen‐derived substrate is reported, which exhibits high transparency (>92%) and high haze (>84%) on account of the micro‐ and nanostructure properties of constituent pollen particles that are readily obtained from nature and require minimal extraction or processing to form the paper‐like substrate based on colloidal self‐assembly. Experiments and simulations confirm that the optical properties of the pollen substrate are tunable and arise from light–matter interactions with the spiky surface of pollen particles. In a proof‐of‐concept example, the pollen substrate is incorporated into a functional perovskite solar cell while the tunable optical properties of the intrinsically micro‐/nanostructured pollen substrate can be useful for a wide range of optoelectronic applications.

Recyclable and Reusable Natural Plant‐Based Paper for Repeated Digital Printing and Unprinting

“…Scanning electron microscopy (SEM) images showed that the toner printed on the pollen paper fused and formed a coating layer with discrete pits, whose micromorphology depended on the print setup (Figure S12a,b, Supporting Information). [ 32 ] Because of the unique intrinsic microstructure of the pollen paper, with its surface roughness, [ 33 ] the fused toner was conformally deposited along the contour of the paper surface (Figure S12c,d, Supporting Information), ensuring a tight bond between the toner and pollen paper with superior resistance to separation (Figure S13, Supporting Information).…”

Extraordinary microcarriers derived from spores and pollens

“…12d). 118 Compared to conventional photovoltaic substrates, the pollen material can achieve versatile and tunable functional properties without complex processing, which makes it an excellent candidate for new environmentally friendly photovoltaic device components. 114 Copyright 2022, Advanced Materials Technologies.…”

“…(d) Schematic illustration and the cross-sectional SEM image of the flexible perovskite solar cell on the nonpressed pollen substrate. Reproduced with permission 118. Copyright 2021, Advanced Materials.…”

Plant‐Based Substrate Materials for Flexible Green Electronics

“…[36][37][38] This unique process uses a pollen-based soft microgel as the building block for natural materials with tunable mechanical, physical, and functional properties. [39][40][41][42] In this study, we demonstrate the feasibility of fabricating and deploying pollen-based materials as unique natural biopolymer substrates for flexible and stretchable electronics. By treating natural pollen with potassium hydroxide (KOH), cellular materials including lipids and proteins can be eliminated, and the hard pollen can be transformed into a non-allergenic, hollow, and soft microgel.…”