Interface engineering is one feasible and effective approach to minimize the interfacial nonradiative recombination stemming from interfacial defects, interfacial residual stress, and interfacial energy level mismatch. Herein, a novel and effective steric-hindrance-dependent buried interface defect passivation and stress release strategy is reported, which is implemented by adopting a series of adamantane derivative molecules functionalized with CO (i.e., 2-adamantanone (AD), 1-adamantane carboxylic acid (ADCA), and 1-adamantaneacetic acid (ADAA)) to modify SnO 2 /perovskite interface. All modifiers play a role in passivating interfacial defects, mitigating interfacial strain, and enhancing device performance. The steric hindrance of chemical interaction between CO in these molecules and perovskites as well as SnO 2 is determined by the distance between CO and bulky adamantane ring, which gradually decreases from AD, ADCA, and ADAA. The experimental and theoretical evidences together confirmed steric-hindrance-dependent defect passivation effect and interfacial chemical interaction strength. The interfacial chemical interaction strength, defect passivation effect, stress release effect and thus device performance are negatively correlated with steric hindrance. Consequently, the ADAA-modified device achieves a seductive efficiency up to 23.18%. The unencapsulated devices with ADAA maintain 81% of its initial efficiency after aging at 60 °C for 1000 h.

BackgroundMicroRNAs are stable and easy to detect in plasma. The plasma levels of microRNAs are often changed in disease conditions, including cancer. This makes circulating microRNAs a novel class of biomarkers for cancer diagnosis. Analyses of online microRNA data base revealed that expression level of three microRNAs, microRNA-24 (miR-24), microRNA-320a (miR-320a), and microRNA-423-5p (miR-423-5p) were down-regulated in colorectal cancer (CRC). However, whether the plasma level of these three microRNAs can serve as biomarkers for CRC diagnosis and prognosis is not determined.MethodsPlasma samples from 223 patients with colorectal related diseases (111 cancer carcinoma, 59 adenoma, 24 colorectal polyps and 29 inflammatory bowel disease) and 130 healthy controls were collected and subjected to reverse transcription-quantitative real time PCR (RT-qPCR) analyses for the three microRNAs. In addition, plasma samples from 43 patients were collected before and after surgical treatment for the same RT-qPCR analyses.ResultsThe concentrations of plasma miR-24, miR-320a and miR-423-5p were all decreased in patients with CRC and benign lesions (polyps and adenoma) compared with healthy controls, but increased in inflammatory bowel disease (IBD). The sensitivity of miR-24, miR-320a and miR-423-5p for early stage of CRC were 77.78 %, 90.74 %, and 88.89 %, respectively. Moreover, the plasma concentration of the three microRNAs was increased in patients after the surgery who had clinical improvement.ConclusionsThe plasma levels of miR-24, miR-320a, and miR-423-5p have promising potential to serve as novel biomarkers for CRC detection, especially for early stage of CRC, which are superior to the currently used clinical biomarkers for CRC detection, such as CEA and CA19-9. Further efforts to develop the three microRNAs as biomarkers for early CRC diagnosis and prediction of surgical treatment outcomes are warrant.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-015-0198-6) contains supplementary material, which is available to authorized users.

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