Skip to main content Accessibility help

Photonic upconversion in solution-processed Gd-based thin films for delayed quantum efficiency roll-off in a-Si flat panel image detectors

  • Nidhi Dua (a1), Soumen Saha (a1) and Madhusudan Singh (a1)


Amorphous Si (a-Si) is used for fabrication of commercial low-cost flat panel image detectors for radiographic applications such as computed tomography (CT) imaging. a-Si photodiodes are known to exhibit a rapid decrease in quantum efficiency near 750nm. While crystalline Si does not suffer from such an early decline, the large-area and low-cost constraints of medical imagers make it challenging and costly to use crystalline Si for such devices. In this work, we report on the development of a sensitive layer for upconversion from 785 nm to green region of the spectrum, which nearly matches the peak quantum efficiency of a-Si detectors. Various host materials have been extensively studied in literature with rare earth ions such as Er3+(emission: green+red), Tm3+(emission: blue), Ho3+(emission: red+green) along with Yb3+ as a sensitizer for upconversion to the visible regime at high incident optical power (∼100 mW) for colloidal solutions. We carried out a thermal decomposition synthesis of NaYF4:Yb(18%),Er(2%),Gd(15%) at moderate temperature (∼320°C), resulting in a nearly pure hexagonal phase material. This is confirmed by powder X-ray diffraction (PXRD) of the unannealed sample with a lattice constant (∼5.17 Å). High-resolution transmission electron microscopy (HRTEM) measurements reveal the formation of nearly spherical nanoparticles. The observed plane ([100]) inferred from lattice fringes in TEM data with a visibly estimated interplanar distance (4.4±1.6 Å) is in reasonable agreement with standard data (∼5.17 Å) for comparable NaYF4-based materials. Excitation (785 nm) of the deposited thin films of Gd-doped unannealed material at relatively low incident power (∼0.4 mW) exhibits a PL response in green (539 nm) and red (665 nm) region of the spectrum. Gd-based upconversion material based thin films are thus a feasible photonic material for potential effective extension of high quantum efficiency range in a-Si for flat panel image detectors.


Corresponding author


Hide All
1Antonuk, L.E., Radiographics 15, 993 (1995).
2Wyrsch, N. and Ballif, C., Semicond. Sci. Technol. 31, 103005 (2016).
3Venkatachalam, R., in Asia-Pac. Conf. (Auckland, New Zealand, 2006), p. 5.
4Parlevliet, D. and Moheimani, N.R., Aquat. Biosyst. 10, 4 (2014).
5Gardelis, S. and Nassiopoulou, A.G., Appl. Phys. Lett. 104, 183902 (2014).
6Bergmann, J., Heusinger, M., Andrä, G., and Falk, F., Opt. Express 20, A856 (2012).
7Rogalski, A., Prog. Quantum Electron. 27, 59 (2003).
8Zhao, W., Ristic, G., and Rowlands, J.A., Med. Phys. 31, 2594 (2004).
9Seibert, J.A., Pediatr. Radiol. 36, 173 (2006).
10Auzel, F., Chem. Rev. 104, 139 (2004).
11Wang, F. and Liu, X., Chem. Soc. Rev. 38, 976 (2009).
12Selvin, P.R., IEEE J. Sel. Top. Quantum Electron. 2, (1996).
13Chen, G., Ohulchanskyy, T.Y., Kumar, R., Ågren, H., and Prasad, P.N., ACS Nano 4, 3163 (2010).
14Wang, L. and Li, Y., Chem. Commun. 0, 2557 (2006).
15Gao, W., Zheng, H., Han, Q., He, E., and Wang, R., CrystEngComm 16, 6697 (2014).
16Jin, L.M., Chen, X., Siu, C.K., Wang, F., and Yu, S.F., ACS Nano 11, 843 (2017).
17Li, Z. and Zhang, Y., Nanotechnology 19, 345606 (2008).
18Wang, H.-Q. and Nann, T., ACS Nano 3, 3804 (2009).
19Wang, F., Han, Y., Lim, C.S., Lu, Y., Wang, J., Xu, J., Chen, H., Zhang, C., Hong, M., and Liu, X., Nature 463, 1061 (2010).
20Singh, V., Kumar Rai, V., and Haase, M., J. Appl. Phys. 112, 063105 (2012).
21Arnaoutakis, G., Marques-Hueso, J., Ivaturi, A., Fischer, S., Goldschmidt, J.C., Krämer, K., and Richards, B., Sol. Energy Mater. Sol. Cells 140, 217 (2015).
22Okyay, A.K., Nayfeh, A.M., Saraswat, K.C., Ozguven, N., Marshall, A., McIntyre, P.C., and Yonehara, T., in LEOS 2006 - 19th Annu. Meet. IEEE Lasers Electro-Opt. Soc. (2006), pp. 460461.
23Paleki A., S.A., EJVES Short Rep. 32, 1 (2016).
24Coffey, V.C., Opt. Photonics News 22, 26 (2011).
25Lay, A., Wang, D.S., Wisser, M.D., Mehlenbacher, R.D., Lin, Y., Goodman, M.B., Mao, W.L., and Dionne, J.A., Nano Lett. 17, 4172 (2017).
26Dua, N., Saha, S., Mehra, M., and Singh, M., in Nanophotonic Mater. XV (International Society for Optics and Photonics, 2018), p. 1072003.
27Kumar, R., Nyk, M., Ohulchanskyy, T.Y., Flask, C.A., and Prasad, P.N., Adv. Funct. Mater. 19, 853 (2009).
28Xing, H., Bu, W., Zhang, S., Zheng, X., Li, M., Chen, F., He, Q., Zhou, L., Peng, W., Hua, Y., and Shi, J., Biomaterials 33, 1079 (2012).
29Nunez Nuria, O., Hernan, Miguez, Marta, Quintanilla, Eugenio, Cantelar, Fernando, Cusso, and Manuel, Ocana, Eur. J. Inorg. Chem. 2008, 4517 (2008).
30Ouyang, J., Yin, D., Cao, X., Wang, C., Song, K., Liu, B., Zhang, L., Han, Y. and Wu, M., Dalton Trans. 43, 14001 (2014).
31Wu, Y., Lin, S., Shao, W., Zhang, X., Xu, J., Yu, L. and Chen, K., RSC Adv. 6, 102869 (2016).
32Dong, B., Song, H., Yu, H., Zhang, H., Qin, R., Bai, X., Pan, G., Lu, S., Wang, F., Fan, L., and Dai, Q., J. Phys. Chem. C 112, 1435 (2008).
33Marble, K., Coker, Z., Yakovlev, V., in 2018 Joint Spring Meeting of the Texas Sections of APS, AAPT, and Zone 13 of the SPS (Bulletin of the American Physical Society 63.
34Battiato, S., Rossi, P., Paoli, P., Malandrino, G., Inorg. Chem. 57, 15035 (2018).
35Cheng, Y.Y., Nattestad, A., Schulze, T.F., MacQueen, R.W., Fuckel, B., Lips, K., Wallace, G.G., Khoury, T., Crossley, M.J., Schmidt, T.W., Chem. Sci. 7, 559 (2016).
36Jia, H., Xu, C., Wang, J., Chen, P., Liu, X., Qiu, J., CrystEngComm 16, 4023 (2014).



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed