Self-Assembled Microhoneycomb Network of Single-Walled Carbon Nanotubes for Solar Cells

Abstract

We propose a water vapor treatment to direct the formation of single-walled carbon nanotubes (SWNTs) into a self-assembled microhoneycomb network (μ-HN) for the application to SWNT-Si solar cells. The μ-HN consists of vertical aggregated SWNT walls and a buckypaper bottom. This hierarchical structure exhibits lower sheet resistance and higher optical transmittance compared with buckypaper. The pristine μ-HN SWNT-Si solar cell shows a record-high fill factor of 72% as well as a power conversion efficiency (PCE) of 6% without optimizing the diameter or height of the vertically aligned SWNTs. The PCE remains stable for weeks under ambient condition, and a PCE exceeding 10% is achieved in the dry state after dilute nitric acid treatment.

Carbon nanotubes for organic/inorganic hybrid solar cells

“…A remarkably high fill factor of 72 % is achieved [124] in SWNTs with self assembled hierarchical microhoneycomb network structure (μ-HN) on n-Si. The hierarchical μ-HN consists of dense walls and a bucky paper bottom, which simultaneously increases the optical transmittance and decreases the sheet resistance.…”

Nano‐Engineering of SWNT Networks for Enhanced Charge Transport at Ultralow Nanotube Loading

“…[5][6][7][8][9][10][11][12][13] In many of these applications, formation of a continuous (percolated) network of interconnected nanotubes inside a polymer fi lm is essential to prevent nanotube aggregation, to promote charge transport through the fi lm and increase performance. [ 14,15 ] Indeed, aggregation reduces the number of pathways for charge transport, and it has been shown to strongly increase junction resistance between tubes. [ 16 ] Ineffi cient mixing and formation of SWNT aggregates moreover increases the amount of nanotubes needed to form continuous pathways between two interfaces, which unnecessarily increases materials cost and lowers performance.…”

Thermal conductivity of chirality-sorted carbon nanotube networks

“…Carbon nanotube films have a broad range of applications, from solar cells 1,2 and transistors 3 to bolometers 4 and mechanical reinforcement additives for polymers. 5 Recent advances have led to sorting of single-walled carbon nanotubes (SWNTs) into chirally purified (i.e., nearly all-semiconducting or all-metallic) solutions and networks.…”