TY - JOUR A1 - Inada, Natsumi A1 - Asakawa, Hitoshi A1 - Kobayashi, Taiki A1 - Fukuma, Takeshi T1 - Efficiency improvement in the cantilever photothermal excitation method using a photothermal conversion layer JF - Beilstein Journal of Nanotechnology PY - 2016/// VL - 7 SP - 409 EP - 417 SN - 2190-4286 DO - 10.3762/bjnano.7.36 PB - Beilstein-Institut JA - Beilstein J. Nanotechnol. UR - https://doi.org/10.3762/bjnano.7.36 KW - atomic force microscopy KW - cantilever excitation KW - dynamic mode KW - photothermal conversion KW - photothermal excitation N2 - Photothermal excitation is a cantilever excitation method that enables stable and accurate operation for dynamic-mode AFM measurements. However, the low excitation efficiency of the method has often limited its application in practical studies. In this study, we propose a method for improving the photothermal excitation efficiency by coating cantilever backside surface near its fixed end with colloidal graphite as a photothermal conversion (PTC) layer. The excitation efficiency for a standard cantilever of PPP-NCHAuD with a spring constant of ≈40 N/m and a relatively stiff cantilever of AC55 with a spring constant of ≈140 N/m were improved by 6.1 times and 2.5 times, respectively, by coating with a PTC layer. We experimentally demonstrate high stability of the PTC layer in liquid by AFM imaging of a mica surface with atomic resolution in phosphate buffer saline solution for more than 2 h without any indication of possible contamination from the coating. The proposed method, using a PTC layer made of colloidal graphite, greatly enhances photothermal excitation efficiency even for a relatively stiff cantilever in liquid. ER -