Abstract
Recent attempts to employ colloidal semiconductor nanocrystals (NCs) as the sensitizing materials for hybrid NC-graphene phototransistors have provided a new effective photosensing platform. However, most of these devices are based on NCs containing either lead or cadmium, which would not be the most preferred material candidates for commercialization. Here, we demonstrate the use of colloidal Cu2-xSe NCs that do not contain lead or cadmium as the sensitizers for NCs-graphene hybrid visible phototransistors. Because the long olyelamine ligands originally attached on Cu2-xSe NCs are known to impede electronic process between NCs and graphene, the long ligands are replaced with short amines including octylamine, hexylamine, and butylamine. It is found that the NCs layer with shorter amine ligands yields a more prominent n-doping effect on graphene under illumination, which results in a systematic negative shift in Dirac voltage. More importantly, this leads to devices with larger photocurrent and larger light responsivity. Consequently, from Cu2-xSe NC-graphene hybrid phototransistors attached with butylamine ligands, responsivity as high as 2600 A/W and photocurrent gain as high as 36 000 are achieved at an optical power of 5 × 10-8 W, which are expected be even larger at lower optical powers. (Figure Presented).
| Original language | English |
|---|---|
| Pages (from-to) | 5436-5443 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry C |
| Volume | 121 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 2017 Mar 9 |
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Energy(all)
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
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Graphene Phototransistors Sensitized by Cu2-xSe Nanocrystals with Short Amine Ligands. / Lee, Juhee; Gim, Yuseong; Yang, Jeehye; Jo, Hyunwoo; Han, Jaehun; Lee, Hojin; Kim, Do Hwan; Huh, Wansoo; Cho, Jeong Ho; Kang, Moon Sung.
In: Journal of Physical Chemistry C, Vol. 121, No. 9, 09.03.2017, p. 5436-5443.Research output: Contribution to journal › Article
TY - JOUR
T1 - Graphene Phototransistors Sensitized by Cu2-xSe Nanocrystals with Short Amine Ligands
AU - Lee, Juhee
AU - Gim, Yuseong
AU - Yang, Jeehye
AU - Jo, Hyunwoo
AU - Han, Jaehun
AU - Lee, Hojin
AU - Kim, Do Hwan
AU - Huh, Wansoo
AU - Cho, Jeong Ho
AU - Kang, Moon Sung
PY - 2017/3/9
Y1 - 2017/3/9
N2 - Recent attempts to employ colloidal semiconductor nanocrystals (NCs) as the sensitizing materials for hybrid NC-graphene phototransistors have provided a new effective photosensing platform. However, most of these devices are based on NCs containing either lead or cadmium, which would not be the most preferred material candidates for commercialization. Here, we demonstrate the use of colloidal Cu2-xSe NCs that do not contain lead or cadmium as the sensitizers for NCs-graphene hybrid visible phototransistors. Because the long olyelamine ligands originally attached on Cu2-xSe NCs are known to impede electronic process between NCs and graphene, the long ligands are replaced with short amines including octylamine, hexylamine, and butylamine. It is found that the NCs layer with shorter amine ligands yields a more prominent n-doping effect on graphene under illumination, which results in a systematic negative shift in Dirac voltage. More importantly, this leads to devices with larger photocurrent and larger light responsivity. Consequently, from Cu2-xSe NC-graphene hybrid phototransistors attached with butylamine ligands, responsivity as high as 2600 A/W and photocurrent gain as high as 36 000 are achieved at an optical power of 5 × 10-8 W, which are expected be even larger at lower optical powers. (Figure Presented).
AB - Recent attempts to employ colloidal semiconductor nanocrystals (NCs) as the sensitizing materials for hybrid NC-graphene phototransistors have provided a new effective photosensing platform. However, most of these devices are based on NCs containing either lead or cadmium, which would not be the most preferred material candidates for commercialization. Here, we demonstrate the use of colloidal Cu2-xSe NCs that do not contain lead or cadmium as the sensitizers for NCs-graphene hybrid visible phototransistors. Because the long olyelamine ligands originally attached on Cu2-xSe NCs are known to impede electronic process between NCs and graphene, the long ligands are replaced with short amines including octylamine, hexylamine, and butylamine. It is found that the NCs layer with shorter amine ligands yields a more prominent n-doping effect on graphene under illumination, which results in a systematic negative shift in Dirac voltage. More importantly, this leads to devices with larger photocurrent and larger light responsivity. Consequently, from Cu2-xSe NC-graphene hybrid phototransistors attached with butylamine ligands, responsivity as high as 2600 A/W and photocurrent gain as high as 36 000 are achieved at an optical power of 5 × 10-8 W, which are expected be even larger at lower optical powers. (Figure Presented).
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U2 - 10.1021/acs.jpcc.7b01212
DO - 10.1021/acs.jpcc.7b01212
M3 - Article
VL - 121
SP - 5436
EP - 5443
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 9
ER -